Daia Zwicky | University of Applied Sciences and Arts Western Switzerland (original) (raw)

Journal papers by Daia Zwicky

Journal of Physics: Conference Series, 2023

Targeting urban and suburban building archetypes, generic but practice-oriented materializations ... more Targeting urban and suburban building archetypes, generic but practice-oriented materializations of basic construction elements (slabs and walls) and their combinations were conceived for heightening of existing buildings by two to four floors. The developed concepts considered numerous construction materials and requirements from architecture, structural engineering, building physics, and fire protection. Evaluations explored the effects on embodied carbon, weight and estimated cost per surface unit of market-oriented element combinations, to identify suitable (and inappropriate) materializations and to detect governing elements and materials. Globally, a heightening by four floors is better than by two, in terms of relative carbon and cost impacts, but some trade-offs in architectural floor plan layout may be required. Seeking cost reductions is generally disadvantageous for embodied carbon while an investment increase does not necessarily provide a reduced carbon footprint. Overall, timber construction results in the lowest embodied carbon (around 5 kg CO2,eq/m 2 •a) while being up to 10% more expensive than the cheapest and up to 15% heavier than the lightest materializations (which depend on the floor plan layout). Lightweight concrete construction can be the most economic materialization but is also up to 200% heavier than the lightest (which can possibly not be supported by the existing building), and results in up to 45% more embodied carbon than constructing with timber.

Construction and Building Materials, May 9, 2022

The reported research explored the feasibility of cold bonding as a method to produce low-embodie... more The reported research explored the feasibility of cold bonding as a method to produce low-embodied-energy lightweight aggregates from locally available biomass wastes (wood sawdust and ashes) and cement, using response surface methodology to model the effect of raw material proportions on the properties of the product. The empirical exploration comprised the particle size distribution, saturated surface dry and oven dry density, water absorption capacity, drying shrinkage, short-(7 days) and long-term (70-days) particle crushing strength, and strength variability of the pellets. Aggregates with particle densities below 1.850 g/cm 3 and crushing strengths above 1.5 MPa (comparable to expanded clay aggregates) were obtained. In the experimental region explored, increasing sawdust contents to decrease aggregate density negatively affected all the other aggregate properties tested. However, the negative impact was strongly reduced by increasing the ratio of coarse particles in the sawdust. Intermixing cement in the raw material mixture as opposed to adding it as a coating to the already formed pellets resulted in better formed, smaller, and stronger pellets, and reduced strength variability. The response model obtained was validated and used to optimize aggregate properties with the specific set of raw materials and production methods studied.

Structural Engineering International, Jul 14, 2020

This study presents the evaluation of various structural analysis approaches to theoretically det... more This study presents the evaluation of various structural analysis approaches to theoretically determine the bending resistance of flexural reinforced concrete elements strengthened with textile-reinforced mortar (TRM), which are gaining more and more attention as external strengthening layers. To assess the increase in capacity due to strengthening, multiple experimental studies from the literature were evaluated. Different structural analysis approaches for determining the flexural strength increase were tested against the experimental data. Finally, the consideration of strain limits for the textile layers, as also applied in the dimensioning of externally bonded fiber-reinforced polymers, proved to be the most reliable analytical approach.

Construction and Building Materials, 2020

The study presented here aimed at improving mechanical properties of wood-cement compounds, basic... more The study presented here aimed at improving mechanical properties of wood-cement compounds, basically consisting of Portland cement and of up to 60% of untreated sawdust, through an aggregate skeleton made of organic aggregates (fruit pits, crushed nut shells) and lightweight aggregates (ex-panded clay and glass). Experimental results show that workability and strength development can be notably improved. Compressive strength can be doubled, and elastic modulus can be tripled. All prop-erties exhibited a marked influence of organic aggregate content. Contextualized comparisons show that the developed alternative lightweight concretes (LC) can be economically competitive with regu-lar LC while the eco-balance is reduced by 70-80%.

Advances in Structural Engineering, Dec 2014

This paper presents recent experimental investigations on structural strengthening by means of (C... more This paper presents recent experimental investigations on structural strengthening by means of (Carbon) Fiber Reinforced Cementitious Matrix (FRCM) in Switzerland. A first test series deals with full-scale reinforced concrete slabs strengthened with one or two composite reinforcement meshes embedded in a shotcrete layer. Static load tests up to failure show the efficiency of the strengthening in terms of increased yield and ultimate load compared to the reference specimen. Due to the
initially necessary straightening of the textile, the contribution at lower deflection levels is limited. Only with advanced cracking and crack opening, the mesh develops its full contribution. Ultimate load is reached after a prompt relative slip of the mesh in the shotcrete. In the post-peak domain, failure by concrete crushing was observed. To study the residual tensile strength of the carbon reinforcement after exposure to high temperatures, various tensile tests on small rovings previously cut out of a composite mesh were performed. The specimens were heated to temperatures of 300 °C, 500 °C, 700 °C, and 1000 °C, kept at that level for 30 minutes, and finally cooled down to room temperature. The subsequent tensile tests performed at room temperature revealed a significant drop in the residual tensile strength for exposure temperature higher than 300 °C. A final test was performed on a reinforced concrete slab strip strengthened with a shotcrete layer including a composite mesh as tensile reinforcement. Under a constant service load, the slab was exposed to fire with a temperature rise according to a European standard curve (ETK) for two hours. The slab could withstand the applied loads for the full two hours, during which the composite mesh reached a temperature of about 440 °C. This observation is consistent with the results from tensile tests on filaments, clearly indicating a residual tensile strength after exposure at a similar temperature. The temperature in the internal steel reinforcement did not trespass a critical value of 500 °C as proposed by current design recommendations.

Applying simplified design code provisions to the shear assessment of existing concrete girders m... more Applying simplified design code provisions to the shear assessment of existing concrete girders may result in unnecessary strengthening, justifying the effort to apply more refined approaches. Based on cross-sectional analysis for continuous girder zones (B-regions), this paper discusses the theoretical influences of the transverse reinforcement ductility and of the effective web concrete compressive strength on shear resistance. It is shown that the plastic deformation capacity is fundamentally influenced by the hardening behavior of the transverse reinforcement and by the bond properties between reinforcement and concrete. For typical examples of stirrup configurations, allowable compression field inclinations are derived and also compared to the provisions of the fib Model Code 2010 and the Generalized Stress Field Approach. The paper concludes with an outlook on practical considerations and how the findings have been integrated in the recently published Swiss code SIA 269/2 on existing concrete structures.

Advances in Concrete Construction, 2013

The first part of this two-part paper discussed some basic considerations on bond strength and it... more The first part of this two-part paper discussed some basic considerations on bond strength and its effect on strain localization and plastic deformation capacity of cracked structural concrete, and analytically evaluated the impacts of the hardening behavior of reinforcing steel and concrete quality on the basis of the Tension Chord Model. This second part assesses the impacts of the most frequently encountered construction details of existing concrete structures which may not satisfy current design code requirements: bar ribbing, bar spacing, and concrete cover thickness. It further evaluates the impacts of the additional structure-specific features bar diameter and crack spacing. It concludes with some considerations on the application of the findings in practice and an outlook on future research needs.

Advances in Concrete Construction, 2013

The applicability of limit analysis methods in design and assessment of concrete structures gener... more The applicability of limit analysis methods in design and assessment of concrete structures generally requires a certain plastic deformation capacity. The latter is primarily provided by the ductility of the reinforcement, being additionally affected by the bond properties between reinforcing steel and concrete since they provoke strain localization in the reinforcement at cracks. The bond strength of reinforcing bars is not only governed by concrete quality, but also by construction details such as bar ribbing, bar spacing or concrete cover thickness. For new concrete structures, a potentially unfavorable impact on bond strength can easily be anticipated through appropriate code rules on construction details. In existing structures, however, these requirements may not be necessarily satisfied, consequently requiring additional considerations. This two-part paper investigates in a theoretical study the impacts of the most frequently encountered construction details which may not satisfy design code requirements on bond strength, steel strain localization and plastic deformation capacity of cracked structural concrete. The first part introduces basic considerations on bond, strain localization and plastic deformation capacity as well as the fundamentals of the Tension Chord Model underlying the further investigations. It also analyzes the impacts of the hardening behavior of reinforcing steel and concrete quality. The second part discusses the impacts of construction details (bar ribbing, bar spacing, and concrete cover thickness) and of additional structure-specific features such as bar diameter and crack spacing.

Structural Engineering International, 2007

recently published by the Swiss Association of Engineers and Architects (SIA) -is applied. This b... more recently published by the Swiss Association of Engineers and Architects (SIA) -is applied. This bulletin introduces so-called performance-based approaches in the Swiss code provisions and allows the application of these displacement-based design methods in the assessment of an existing building under earthquake loading. In order to reach economically feasible recommendations for risk-reduction measures, the technical bulletin also allows the investigation of the commensurability and the reasonableness of such measures.

Journal of Structural Engineering-asce, 2006

In design for shear forces with stress fields, three failure criteria are usually considered: fai... more In design for shear forces with stress fields, three failure criteria are usually considered: failure of the chords, of the compression struts, and of the stirrups. Bond failure along the chords is usually not explicitly checked. The effective concrete strength in the struts and the bond strength along the chord are combined with the stresses in the stirrups to determine critical inclinations of the compression struts. An expression for the effective concrete strength is proposed considering compression softening, while the proposed expression for bond strength considers concrete strength, bar roughness, and the beneficial effect of lateral pressure exerted by the stirrup forces. Parametric studies are discussed and conclusions are drawn on the governing failure criteria and the critical inclination of the compression struts in the ultimate limit state. An Appendix summarizes the calibration of the proposal for the effective concrete compressive strength and compares it to other proposals from the literature.

Starting from the investigation of the simple case of a cantilevered road deck, this paper attemp... more Starting from the investigation of the simple case of a cantilevered road deck, this paper attempts to demonstrate that deeper investigations of a structural safety problem may lead to significant modifications of the goals of the investigation.The assignment by the owner authority consisted of assessing the bending moments due to traffic loads, above all from axle loads, at the clamping of a cantilevered slab and to propose appropriate measures if needed. The slab carries the road deck, being the hard shoulder of the Swiss North–South motorway close to the Italian border.In a first step, the regular axle loads of the new Swiss action code are applied to calculate the inner forces by simple hand calculations. It is found that the shear resistance is noticeably more critical than the bending resistance, considering both the new Swiss structural concrete code as well as, for reasons of comparison, Eurocode 2.In a second step, the reduction of the axle loads is investigated considering actualised load models developed for the assessment of existing road bridges. It is found that applying these models achieves structural safety in large parts of the structure, but that other parts still exhibit insufficient structural safety.In the third part, the possible range of strengthening measures is investigated. It is pointed out that every strengthening method should be carefully checked for its application conditions and the corresponding consequences. Qualitative criteria are adequate to judge a specific strengthening method in a certain situation. The last part of the paper discusses the effectively executed measures.Conclusions on the application of the findings from the paper to other assessment situations are drawn.

Conference papers by Daia Zwicky

International Conference on Concrete Sustainability, 2024

This study explored the potential of using high-calcium grate ash and fly ash from wood combustio... more This study explored the potential of using high-calcium grate ash and fly ash from wood combustion in combination with metakaolin and limestone as a replacement material for cement in low-clinker binders. Three products were investigated: sand mortars and lightweight mortars,
as well as pellets in order to obtain lightweight, low-clinker, and waste-embedding aggregates. In mortars, the sulphur- and potassium-rich fly ash was found to be detrimental to the strength, even at low amounts (5%), whereas the grate ash could replace up to 15% of cement in a binder. This addition improved early age strength but rather acts as a filler at later age. Slaking the ash before blending was found not to be necessary, although it slightly improved mechanical performance. Lightweight mortars were explored by replacing sand with sawdust, another
byproduct from the timber transformation chain. Low densities
(of 900-1500 kg/m3) could be obtained, but it was also shown that these
lightweight materials would be better suited for non-structural applications, such as thermal insulation. A batch of lightweight aggregates based on these mortars was produced through pelletizing, obtaining a material with properties close to that of low-grade expanded clay aggregates.

IABSE Symposium 'Construction’s Role for a World in Emergency', 2024

The use of lightweight concrete could overcome some of the disadvantages of normal-weight concret... more The use of lightweight concrete could overcome some of the disadvantages of normal-weight concrete. However, the fabrication of lightweight aggregates is energy intensive and considerably draws on non-renewable resources. The positive consequences from lighter weight on supporting structural components' dimensions are frequently outrun by the increase in carbon footprint of up to 65% stemming from the lightweight aggregates. On this background, fabrication of lightweight aggregates in a low-energy cold-bonding pelletizing process, using bio-based waste and byproducts, and alternative binders in combination with or instead of cement was explored. Presented results cover reflections for recipe mix design, observations made in the pelletizing and hardening process, results obtained for density, strength, thermal properties, and carbon footprint of this alternative way to produce lightweight aggregates for concrete.

2nd Int’l Conference of Sustainable Building Materials, Aug 15, 2019

It is difficult to compete with normalweight concrete: it is pourable, usually self-compacting, h... more It is difficult to compete with normalweight concrete: it is pourable, usually self-compacting, hardening reasonably fast, cheap and locally available in large quantities. Its excellent fire protection and good acoustic insulation for airborne sound are further advantages in construction. But, regular concrete is very heavy, being disadvantageous for transportation and hoisting and results in the fact that a concrete structure predominantly supports its self-weight. Also, concrete qualities applied in building construction usually provide a far too high strength, as geometry is often dictated by constructability (minimum dimensions for concreting). Concrete further provides poor thermal insulation and unpleasant user experience (it "feels" cold), and is rather challenging to recycle. Last but not least, concrete manufacture is largely based on non-renewable resources and has a high environmental impact. Thus, alternative lightweight concretes should be further developed. Starting from earlier developments on "wood-based concrete" (or wood-cement compounds WCCs), essentially consisting of Portland cement (PC) and other mineral binders and of up to 60% of untreated sawdust, this study aimed at improving their mechanical properties by integrating an aggregate skeleton from organic aggregates (fruit pits, crushed nut shells) and lightweight aggregates from largely available or renewable resources (expanded clay and glass). 15 different recipes for "WooCon" (from wood-concrete) were designed and evaluated, in a first phase, for possible self-compaction as a basic fresh-state requirement for their targeted application in prefabrication. In a second phase, basic mechanical properties of 5 retained WooCon recipes were evaluated, by testing elastic modulus, compressive strength, and their development over 28 days as a further important prefabrication requirement. These results were also used to modify predictive expressions for correlating compressive strength and elastic modulus. In a third phase, estimates of economic and ecological performances were established, in order to assess the competitiveness of the newly developed WooCon recipes. The fourth evaluation phase of long-term properties (shrinkage and creep) of the 3 most promising WooCon recipes is currently ongoing. The study results show that adding an aggregate skeleton to WCCs, i.e. converting them into WooCon, can notably improve workability properties, up to self-compaction. Compressive strength can be doubled and elastic modulus can be tripled. Strength development can be predicted by generally accepted expressions and can even reach very rapid early hardening. Elastic modulus can be correlated quite accurately to compressive strength. In all evaluated mechanical properties, a marked influence of the applied percentage of organic aggregates could be observed. Economic impacts of WooCon majorly reside in costs for organic aggregates and cement, and result in unit prices up to 2.5 times higher than regular lightweight concrete (LC); however, if contextualised for mechanical elements, WooCon can perform better than regular LC. Lime filler and cement are the major contributors to ecological impact (global warming potential, GWP) but the overall result shows 75-80% reductions in comparison to regular LC.

IABSE Congress 'The Evolving Metropolis', 2019

According to Swiss code SIA 262 "Concrete structures", stirrups of reinforced concrete beams must... more According to Swiss code SIA 262 "Concrete structures", stirrups of reinforced concrete beams must "surround the tensile longitudinal reinforcement" and must "be anchored to mobilize the static height of internal forces". For existing concrete structures, Swiss code SIA 269/2 provides stirrup detailing requirements while limiting these directives for stirrup anchorage to the compression zone. In zones of negative bending, these requirements are often not satisfied for execution reasons. This question is addressed in a largely experimental Ra&D project. Anchorage tests were performed and analyzed, with a total of 144 tests on 9 concrete beams. These underwent a longitudinal tensile force up to 1'000 kN to simulate transverse cracking at stirrup anchorages in negative flexure zones. The study parameters are crack width (0, 0.4 and 0.9 mm), stirrup diameter (10 and 14 mm), bar ribbing (smooth and ribbed) and hook angle (90°, 135°, 180° and straight bars). A design model based on the "tension chord model" (TCM) developed at ETH Zurich is proposed. This simple and practical design model has proved its effectiveness to consider bond effects. Reduction factors for bar diameter, relative bar ribbing, hook effect and crack width were taken into account for calibration. Results of analytical calculations are coherent with experimental tests.

Life-Cycle Analysis and Assessment in Civil Engineering: Towards an Integrated Vision, Oct 2018

When strengthening reinforced concrete slabs with textile reinforced mortars (TRM), the " correct... more When strengthening reinforced concrete slabs with textile reinforced mortars (TRM), the " correct " consideration of the global bond behaviour between textile and cementitious matrix is identified as the main challenge in determining the most appropriate global analytical model. The first model evaluated here is based on classical assumptions for structural concrete design. The second model, as another extreme assumption, is completely neglecting textile bond in the cracked zone, thus assuming it as unbonded, end-anchored, external reinforcement. The third model is based on the simplifying assumption of the textile reinforcement being only significantly activated when the internal steel reinforcement is yielding. Analytical results from these approaches are compared to a database containing more than 130 test results reported in literature, and are statistically evaluated.

Glass fibre reinforced polymers (GFRP) were developed in the first half of the 20th century. They... more Glass fibre reinforced polymers (GFRP) were developed in the first half of the 20th century. They have high strength (especially for tensile stresses), low density, high resistance in corrosive environments, and free formability. Despite these advantages, GFRP materials are not widely used in construction yet. The main reasons are low stiffness of GFRP (relative to its strength) and the absence of codified and generally
accepted design standards. Structural engineers typically have limited knowledge and experience with these materials. In this study, an approach to design slender GRFP bracing panels with methods similar to those used for plated steel girders is developed and compared to results of full-size shear tests.

2nd Concrete Innovation Conference

For the advancement of sustainable, cement-based construction of buildings, composite elements ma... more For the advancement of sustainable, cement-based construction of buildings, composite elements made of timber and wood-cement compound (WCCs) are developed at iTEC since 2012. Earlier research on recipe development, workability, mechanical properties and recyclability trough combustion of WCCs shows that this material is usable as construction material and not just as material for finishing layers. After studies on structural behavior and eco-balance of single-span timber-WCC composite (TWCCC) slab elements, as well as tests to determine the building-physical performance of WCCs and the structural behavior and design of story-high TWCCC wall elements, one wants to know if it is possible to reinforce WCC to apply it in continuous slab elements. To further extend the application domain of TWCCC-based construction, different concepts for continuous TWCCC slab elements are currently developed and evaluated, in collaboration with an industrial partner. As certain zones of the WCC section in these structural systems will be loaded in flexural tension, provision of reinforcement is principally required. As WCCs provide rather little strength and stiffness, existing concrete design rules for anchorage, crack width calculation etc. may not necessarily be applicable. Furthermore, applicability of alternative reinforcement material should also be considered, as required by the industrial partner. With this background, pull-out tests were performed on specimens with long bond length of traditional steel reinforcing mesh as well as timber battens, untreated and planed, as reinforcement. The paper shows and discusses test setup and results of these pull-out tests. It further shows first parts of a bond stress-slip law. The paper concludes by identifying remaining research challenges in view of a practical application of reinforced WCC.

Story-high, prefabricated concrete façade elements with 6-8 cm thick outer layers were frequently... more Story-high, prefabricated concrete façade elements with 6-8 cm thick outer layers were frequently used in building construction in the 1960/70s. In current construction and rehabilitation, they are much thicker (12-15 cm) or economically non-competitive, due to significantly increased concrete cover or the required use of stainless steel reinforcement, respectively, for durability. Additionally, these elements are placed further away from the support structure, owing to significantly increased requirement in thermal insulation. The outer shell of a façade element of the late 1960s was 4-8 cm away from the support structure while today, it is placed at a distance of 16-32 cm. The potential of replacing steel bars in prefabricated concrete façade elements by non-metallic glass-fiber reinforced polymer (GFRP) reinforcement was explored experimentally in a collaborative research project, targeting 5 cm thin elements and also requiring to test an associated new anchor system.

Journal of Physics: Conference Series, 2023

Construction and Building Materials, May 9, 2022

Structural Engineering International, Jul 14, 2020

Construction and Building Materials, 2020

Advances in Structural Engineering, Dec 2014

Advances in Concrete Construction, 2013

Structural Engineering International, 2007

Journal of Structural Engineering-asce, 2006

International Conference on Concrete Sustainability, 2024

IABSE Symposium 'Construction’s Role for a World in Emergency', 2024

2nd Int’l Conference of Sustainable Building Materials, Aug 15, 2019

IABSE Congress 'The Evolving Metropolis', 2019

Life-Cycle Analysis and Assessment in Civil Engineering: Towards an Integrated Vision, Oct 2018

2nd Concrete Innovation Conference

Cement-bonded wood products are used in construction since the beginning of the 20 th century. Un... more Cement-bonded wood products are used in construction since the beginning of the 20 th century. Until today, however, they are essentially applied as non-structural finishing layers, e.g. as support for stucco, as fire protection or acoustic insulation panels, providing good fire resistance, thermal and acoustic insulation properties with a relatively low and thus, structurally advantageous material density. If to be applied structurally, these materials should not be regarded as substitution material for regular structural concrete but rather be used in composite elements. They also exhibit rather low stiffness and strength properties. Structural wood-cement compounds (WCCs) may also provide further functional features e.g. contributing to thermal and acoustic insulation or fire protection, thereby compensating for their reduced mechanical properties. The contribution presents results from different tests performed with the objective to determine short-and long-term mechanical properties, thermal insulation, specific heat capacity, acoustic insulation, and combustibility features of WCC-based constructions. It further examines and assesses the economic and ecological potential of WCC-based structural elements and discusses potential challenges in the structural use of WCCs.

Cement-bonded wood-based materials (wood-cement compounds, WCCs) are used in construction since m... more Cement-bonded wood-based materials (wood-cement compounds, WCCs) are used in construction since more than 100 years. Until today, they are chiefly used non-structurally where their good fire resistance, thermal and acoustic insulation and thermal mass are combined with a relatively low density. Main application forms of WCCs are prefabricated panels but pour-able mixes are also available. WCCs allow creating light-weight structural elements if applied, for example, in composite timber-WCC elements. Such multi-functional elements cannot only fulfill a structural task but provide also building-physical performances. This paper reports on test results for thermal insulation and specific heat capacity of WCCs and timber-WCC walls, also comparing them to performance features of other construction materials and code requirements. The paper also presents results from full-scale buckling tests, and evaluates the suitability of structural design approaches. This contribution is complemented by companion papers on me-chanical properties of WCCs and performance features of timber-WCC slab elements.

Cement-bonded wood-based materials (Wood-Cement Compound: WCC) are used in construction since the... more Cement-bonded wood-based materials (Wood-Cement Compound: WCC) are used in construction since the beginning of the 20th century already. Until today, however, they are chiefly used as non-structural finishing layers where their good fire resistance, thermal and acoustic insulation properties are combined with a relatively low and thus, structurally benefi-cial density. WCCs should not be seen as an alternative to regular structural concrete – as stiff-ness and strength of WCCs usually are rather low – but should rather be applied in structural el-ements with composite action, e.g. together with timber or other light-weight structural elements (to not unnecessarily increase the overall weight). This article reports on results from full-scale tests up to failure on timber-WCC composite slab elements and compares their structural per-formance to more traditional timber-concrete composite slabs. Test results for determining acoustic insulation properties of timber-WCC slab elements are also presented as well as an eco-balance analysis.

Wood-cement compounds (WCCs) are composite materials made of wooden ag-gregates and mineral (ceme... more Wood-cement compounds (WCCs) are composite materials made of wooden ag-gregates and mineral (cement) binders. These materials are widely used as prefabricated panels in the construction industry. A main obstacle for using casted WCC in construction elements is high shrinkage of the young product and frequently difficult workability of the mixes. This pro-ject addresses both of these problems by developing self-compacting low-shrinkage WCCs. An-other objective of the study is to reduce cement content, which is typically very high in WCCs (500 to 700 kg/m3 of Portland cement). By replacing Portland cement with inert fillers or poz-zolanic waste materials, the environmental impact of the WCCs can be lowered and a “greener” cement-based material is created. To assess the effectiveness of the developed recipes, WCC specimens are evaluated with regard to shrinkage, workability and mechanical performance.

Wood-cement compounds (WCCs) have been being used in construction since the beginning of the 20 t... more Wood-cement compounds (WCCs) have been being used in construction since the beginning of the 20 th century, mostly as a secondary structure or finishing layers such as sound or thermal insulation elements. However, WCCs' stiffness and strength are rather low, therefore WCCs should be combined with timber or a similar lightweight structural material used as a load-bearing element. The use of WCC for composite elements allows to take advantage of both materials, particularly of the strength of timber and the insulation properties of WCC. Furthermore, WCC slab elements do only require a minimal secondary structure due to their beneficial sound and thermal insulation properties. This paper reports on a life-cycle assessment (LCA) where those new and promising composite slab elements have been compared to traditional concrete, wood and timber-concrete composite (TCC) slabs regarding greenhouse gas emissions (EGG), non-renewable primary energy (NRPE) and environmental impact points (UBP).

10th Conference on Advanced Building Skins

The most widely used construction material is reinforced concrete which is heavy, has rather high... more The most widely used construction material is reinforced concrete which is heavy, has rather high embedded carbon, strongly draws upon non-renewable resources, is challenging to re-use, and exhibits rather poor building-physical properties. A high potential for a more sustainable development of building construction is located in timber-based composite structures. These should be, however, not be produced with regular concrete, as this still introduces the mentioned disadvantages. Mixes of cement with wood components, socalled wood-cement compounds (WCC), may be one of the answers for an even more sustainable evolution of timber-concrete composite construction. Some of the non-renewable parts (gravel, sand) of concrete are substituted with renewable ones in WCCs, with the objective to create a light-weight, pourable, selfcompacting, cheap, easily recyclable, and thus, "greener" cement-based construction material that has further benefits with regard to building-physical properties to be exploited in so-called hybrid structural elements. This paper reports on results of laboratory testing for determining short-and long-term mechanical properties of newly developed WCC recipes, i.e. density, elastic moduli, compressive and tensile strength, shrinkage, and creep properties. Furthermore, their economic feasibility is assessed as well and potential challenges in structural applications of WCCs are pointed out.

10th Conference on Advanced Building Skins

Wood-cement compounds (WCCs) contain 30% to 40% combustible matter. Consequently, it is essential... more Wood-cement compounds (WCCs) contain 30% to 40% combustible matter. Consequently, it is essential to determine if this kind of material is able to burn and produce energy as a way of recycling. Therefore, explorative combustibility tests were performed on three different WCCs. The ignition temperature is around 210°C, independently of the WCC recipe. Combustion stops at removal from the furnace. WCCs can thus be considered difficultly inflammable and may therefore serve as a fire protection layer. Available calorific values between 3 and 6 MJ/kg are significant, and also clearly show a beneficial effect of activated charcoal. The energy required for grinding as a preparation for combustion is almost negligible. The time for complete combustion is a function of furnace temperature, density and calorific value of WCC. Ash content, i.e. inorganic residue, is rather important with 55% or higher. Optimal combustion conditions primarily depend on material density and furnace temperature. Combustion fumes do not show particular pollutants. CO2 and NOx emissions are more than proportional at temperatures beyond 800°C or if the WCC contains activated charcoal, respectively. NOx emission during combustion may be a potential problem and should be considered in the design of the combustion process.

10th Conference on Advanced Building Skins

Timber construction has become more and more competitive by adapting efficient prefabricated cons... more Timber construction has become more and more competitive by adapting efficient prefabricated construction methods and by recent changes in fire protection norms. Until recently, multy-story buildings had to contain an escape route built in non-combustible materials. Nowadays, the fire protection rules veer towards performance-oriented criteria, as seen recently with the changes of Swiss fire protection specifications. However, cladding of the structure is still necessary in most cases and it is usually necessary to fill voids of the structure with non-structural materials, such as mineral wools etc. Massive structures that incorporate the fire cladding functions and add to thermal inertia while still retaining some degree of insulation and can, due to their low weight, be easily integrated into the prefabricated timber-construction process could have a big potential in timber construction.

4th International Conference on Concrete Repair, Rehabilitation and Retrofitting

The roofing of an office building partially collapsed after being in use for almost twelve years.... more The roofing of an office building partially collapsed after being in use for almost twelve years. The author was appointed as an independent structural expert to investigate the damage event, by approval of all involved parties, i.e. owner, building insurer and roof constructor. The expert report should give answers to several questions related to forensic engineering, e.g. reasons for the partial failure of the roof elements; influence of the snow load present at the moment of partial collapse; faults or deficits in the structural concept, in element production or execution etc. The paper reports on the course of events and actions, the structural and architectural conception of the roofing, its structural behavior, determination of updated failure loads, associated structural safety assessment and degrees of compliance. The paper gives no conclusion on legal or insurance issues.

fib-CH – Structural Concrete in Switzerland, section ‘Research & development – HEIA-FR/iTEC, 2018

Next Generation Design Guidelines for Composites in Construction – State-of-the-Art, May 26, 2017

The Institute of Construction and Environmental Technologies (iTEC) of the School of Engineering ... more The Institute of Construction and Environmental Technologies (iTEC) of the School of Engineering and Architecture Fribourg (HEIA-FR) is active in research on structural applications of FRP composites since almost 20 years, initially guided by Prof. em. René Suter and since 10 years by the author.
Several R&D projects explore different possibilities of FRP applications in new structural elements and strengthening of existing, of which a selection is presented hereafter. Structural applications of fibre-reinforced cementitious matrix (FRCM), other uses of FRP products as well as full FRP girder elements are also ongoing at iTEC but not further reported here.

Betonkalender 2015, 104. Jg., Vol. 2, p. 907-936, Dec 2014

SIA D0240: Erhaltung von Tragwerken – Vertiefung und Anwendung, 2011

Verweise auf Ziffern der Norm SIA 269/2 [1] werden in Kursivschrift ohne wiederholte Quelleangabe... more Verweise auf Ziffern der Norm SIA 269/2 [1] werden in Kursivschrift ohne wiederholte Quelleangabe dargestellt. + a) b) Erhaltung von Tragwerken -Betonbau: Einführung in die Norm SIA 269/2 Damit die Biegetraglast -und damit die maximal mögliche Querkraft + act d V , (Bild 1) -nicht unterschätzt wird und somit vorzeitiges Querkraftversagen ausgeschlossen werden kann, fordert Ziffer 4.3.1.4.2 die zu Norm SIA 262 [2] sinngemässe Berücksichtigung von Überfestigkeiten in der Ermittlung der Biegewiderstände + act Rd M , . Gemäss Norm SIA 262 [2], Ziffer 4.3.9.3.3, sind in der Ermittlung der Biegewiderstände + act Rd

SIA D0240: Erhaltung von Tragwerken – Vertiefung und Anwendung, 2011

SIA D0240: Maintenance des structures porteuses – perfectionnement et exemples, 2011

Les renvois aux chiffres de la norme SIA 269/2 [1] sont marqués en italique afin d'éviter la répé... more Les renvois aux chiffres de la norme SIA 269/2 [1] sont marqués en italique afin d'éviter la répétition de la référence.

SIA D0240: Maintenance des structures porteuses – perfectionnement et exemples, 2011

Regenerative Technologies towards Sustainable Development Goals, 2019

IBI seminar, ETH Zurich

BetonTage 2018, 2018

Keynote given at 62. BetonTage 2018, Neu-Ulm (Germany)

UFPB, Assemblée d’automne, HEIA, Fribourg CH

Im Beitrag wird ein neues Verstärkungssystem, bestehend aus in Spritzmörtel verlegten Carbongitte... more Im Beitrag wird ein neues Verstärkungssystem, bestehend aus in Spritzmörtel verlegten Carbongittern, vorgestellt; dieses System weist gegenüber den üblichen Techniken geklebter Lamellen aus carbonfaserverstärktem Kunststoff (CFK) grosse Vorteile beim Einbau auf. In einer grossmassstäblichen Versuchsreihe mit einem unverstärkten Referenzträger und zwei unterschiedlich verstärkten Plattenstreifen wurde die statische Effizienz des neuen Verstärkungssystems geprüft. Die Resultate zeigen, dass grundsätzlich beachtliche Verstärkungsgrade erzielen lassen; der Tragwiderstand der Carbongitter kann aber mit etwa 17% der theoretischen Zugfestigkeit bei weitem nicht ausgenützt werden. Dies ist einerseits darauf zurückzuführen, dass die Carbongitter infolge des schlaffen Einbaus eine anfängliche Streckung benötigen; andererseits ist die Verbundsteifigkeit zwischen Carbongitter und Spritzmörtel gering, so dass die Carbongitter eher als an den Enden verankerte, verbundfreie Zugglieder wirken. Die Versuche lassen vermuten, dass das Versagen der Verstärkungen im Verbund in den Verankerungsbereichen erfolgt, und damit zu einem schlagartigen Abfall der Gesamtlast führt.

Bei der Bemessung von Holzbalken wird oft der Nachweis der Gebrauchstauglichkeit (Durchbiegungen)... more Bei der Bemessung von Holzbalken wird oft der Nachweis der Gebrauchstauglichkeit (Durchbiegungen) massgebend; der verfügbare Tragwiderstand kann nur selten ausgenützt werden. Dies beruht zum grossen Teil darauf, dass Holz als natürliches Baumaterial grosse Streuungen aufweist und ein eher ungünstiges Verhältnis von Steifigkeit und Festigkeit zeigt. Wegen dieser relativ hohen Streuungen sind die für die Bemessung benötigten charakteristischen Werte vergleichsweise tief angesetzt. Gewisse Verbesserungen im Gebrauchstauglichkeitsverhalten werden erzielt, wenn Querschnitte aus Brettschichtholz (BSH) anstelle von Massivholzquerschnitten verwendet werden; dennoch bleibt die Steifigkeit in der Regel zu tief, als dass die verfügbaren Tragwiderstände ausgenützt werden könnten.
Dieser Mangel an Steifigkeit resp. die Massgeblichkeit des Nachweises der Gebrauchstauglichkeit gab den Anstoss für die Entwicklung eines neuen Verbundelements: BSH niedrigster Qualität wird mit vorgespannten CFK-Lamellen (Lamellen aus carbonfaserverstärktem Kunststoff) verstärkt. Nachfolgend wird über die Resultate von grossmassstäblichen Tastversuchen berichtet, welche an der HTA-FR durchgeführt wurden, und das Tragverhalten der Balken bezüglich Gebrauchstauglichkeit und Tragsicherheit analysiert. Der Beitrag wird durch einen Ausblick auf anverwandte, aktuelle Forschungsarbeiten sowie Hinweise für weitere Forschungsbedürfnisse abgeschlossen.

Dimensions, 2024

Based on interview with D. Zwicky

Construction Research and Innovation, 2017

Based on an interview with Daia Zwicky

Tages-Anzeiger, 2017

Zeitungsartikel zu Interview mit D. Zwicky (J. Laukenmann)

Holz-Zentralblatt, 2017

(basierend auf persönlicher Kommunikation mit D. Zwicky)

http://blog.allplan.com/de/holzbeton

Deutschlandfunk - Forschung aktuell vom 20.09.2017 (gekürzte Fassung)

RTS téléjournal 19h30 du 18.09.2017

Tagesschau Spätausgabe Wochenende vom 17.09.2017 (@ 6'38")

Resarch report, Jul 18, 2024

This study is part of the "Net-zero greenhouse gas emissions in the building area" research proje... more This study is part of the "Net-zero greenhouse gas emissions in the building area" research project of the Swiss Federal Office of Energy. The present research question F2, focusing on a bottom-up view, aims to define net-zero greenhouse gas (GHG) strategies, establish benchmarks, and guide stakeholders towards net-zero practices at building scale. The project objectives include identifying measures to reduce GHG emissions from construction and operation at building scale, formulating strategies for achieving net-zero GHG by 2050, assessing these strategies from a social, economic, and technical point of view, and classifying building standards in relation to net-zero targets. A systematic approach, including a literature review, logical grouping, and data collection, was employed to identify measures for greenhouse gas emissions reduction and their effectiveness. Existing recommendations and scientific literature were reviewed to have a comprehensive list of measures available. Results throughout the report are based on a life cycle assessment approach. Measures are assessed considering their relevance in relation to emissions at building scale and the limitations involved with the available data and the implementation of single measures. Finally, recommendations are drawn for each measure, offering a detailed perspective on the challenges and opportunities in the pursuit of net-zero construction practices. The measures are then assessed with feasibility indicators for economic, social, and technical dimensions. The feasibility assessment aims to provide an indication on the degree of enabling and barrier conditions for the swift implementation of the measures to achieve net-zero at building level in a life cycle perspective. In accordance with the feasibility results, measures are finally combined into strategies reflecting different levels of efforts from different stakeholders and different societal perspectives. In parallel to the assessment of measures and strategies to reduce GHG emissions, building standards and labels available in the Swiss context are examined to highlight potential discrepancies with the net-zero targets. A key takeaway from our analysis is the recognition that achieving net-zero emissions at the building scale is a complex task. The stark reality is that no single measure, in isolation, possesses the capability to attain net-zero status unless, of course, we cease construction activities altogether or achieve a complete decarbonization of the energy supply including supply chain emissions. This underscores the need for a holistic approach that integrates a combination of measures, carefully tailored to address specific constraints, requirements, and opportunities. Single measures have the potential to achieve an average 15% reduction in greenhouse gas emissions in a reference new multi-family house building while a holistic approach of utilizing the full range of measures could bring down the impact by up to 72% today. 4/111 Zusammenfassung Diese Studie ist Teil des Forschungsprojekts «Netto-Null Treibhausgasemissionen im Gebäudebereich» des Bundesamts für Energie. Die vorliegende Fragestellung F2, die sich auf eine Bottom-up Betrachtung konzentriert, zielt darauf ab, Strategien für Netto-Null Treibhausgasemissionen zu definieren, Benchmarks festzulegen und die Beteiligten auf Netto-Null Praktiken hinzuweisen. Zu den Projektzielen gehören die Suche nach Massnahmen zur Verringerung der Treibhausgasemissionen aus Erstellung und Betrieb von Gebäuden, die Festlegung von Strategien zur Erreichung von Netto-Null-Treibhausgasemissionen bis 2050, die Bewertung dieser Strategien aus sozialer, wirtschaftlicher und technischer Sicht sowie die Klassifizierung von Gebäudestandards in Bezug auf Netto-Null-Ziele. Ein systematischer Forschungsansatz, der eine Literaturrecherche, eine logische Gruppierung und eine Datenerhebung umfasste, wurde angewandt, um Massnahmen zur Reduktion von Treibhausgasemissionen und deren Wirksamkeit zu ermitteln. Existierende Empfehlungen und wissenschaftliche Literatur wurden geprüft, um eine umfassende Liste von Massnahmen zur Verfügung zu haben. Die Ergebnisse in diesem Bericht basieren auf einem Lebenszyklusansatz. Die Massnahmen werden unter Berücksichtigung ihrer Relevanz in Bezug auf die Emissionen auf Gebäudeebene und der Einschränkungen, die mit den verfügbaren Daten und der Umsetzung der einzelnen Massnahmen verbunden sind, bewertet. Schliesslich werden für jede Massnahme Empfehlungen erstellt, die einen detaillierten Überblick über die Herausforderungen und Chancen bei der Realisierung von Netto-Null-Bauweisen geben. Die Massnahmen werden dann anhand von Machbarkeitsindikatoren für wirtschaftliche, soziale und technische Aspekte bewertet. Die Machbarkeitsstudie soll Aufschluss darüber geben, inwieweit die Voraussetzungen für eine rasche Umsetzung der Massnahmen zur Erreichung von Netto-Null auf Gebäudeebene in einer Lebenszyklusbetrachtung gegeben sind. In Übereinstimmung mit den Ergebnissen der Machbarkeitsstudie werden die Massnahmen schliesslich zu Strategien zusammengefasst, die die unterschiedlichen Aktivitäten der verschiedenen Interessengruppen und die verschiedenen gesellschaftlichen Perspektiven widerspiegeln. Gleichzeitig mit der Beurteilung von Massnahmen und Strategien zur Reduktion der Treibhausgasemissionen werden die in der Schweiz verfügbaren Standards und Labels untersucht, um mögliche Diskrepanzen zu den Netto-Null-Zielen aufzuzeigen. Eine der wichtigsten Schlussfolgerungen aus unserer Analyse ist die Erkenntnis, dass das Erreichen von Netto-Null-Emissionen auf der Gebäudeebene eine komplexe Aufgabe ist. Die Realität sieht jedoch so aus, dass keine einzelne Massnahme für sich genommen in der Lage ist, den Netto-Null-Status zu erreichen, es sei denn, wir stellen die Bautätigkeit ganz ein oder erreichen eine vollständige Dekarbonisierung der Energieversorgung einschliesslich der Emissionen der Lieferkette. Dies verdeutlicht die Notwendigkeit eines ganzheitlichen Ansatzes, der eine Kombination von Massnahmen umfasst, die sorgfältig auf die spezifischen Einschränkungen, Anforderungen und Möglichkeiten zugeschnitten sind. Einzelne Massnahmen haben das Potenzial, die Treibhausgasemissionen in einem Referenz-Mehrfamilienhaus Neubau, um durchschnittlich 15 % zu senken, während ein ganzheitlicher Ansatz, bei dem die gesamte Bandbreite an Massnahmen genutzt wird, die Auswirkungen um bis zu 72 % reduzieren könnte. Während die Machbarkeit dieser Massnahmen und Strategien aus technischer Sicht grösstenteils in Reichweite ist, bestehen die wesentlichen Hindernisse in sozialen und wirtschaftlichen Bereichen. Die Umsetzung von Netto-Null-Praktiken im Baubereich steht vor Herausforderungen, die in der gesellschaftlichen Haltung, wirtschaftlichen Überlegungen und der Trägheit bestehender Systeme begründet sind. Um diese Hürden zu überwinden, bedarf es gemeinsamer Anstrengungen verschiedener Interessengruppen, darunter politische Entscheidungsträger, Industrievertreter, Planer und die Öffentlichkeit. Der aktuelle Kontext von Standards und Labels ist noch nicht speziell auf Netto-Null-Treibhausgasemissionen ausgerichtet. Die neue Norm prSIA 390/1 (in Überarbeitung) ist insofern auf die Netto-Null-Ziele abgestimmt, als sie spezifische Treibhausgasgrenzwerte und-ziele für Erstellung und Betrieb vorschlägt, obwohl der Weg zu Netto-Null derzeit nur in einem rein informativen Anhang erwähnt wird. Zwischen den bestehenden Standards und Labels bestehen Diskrepanzen in Bezug auf 5/111 Methoden, Grenzen und Zieldefinitionen, so dass eine Harmonisierung erforderlich ist. Zusammenfassend lässt sich sagen, dass der Weg zu Netto-Null Treibhausgasemissionen von Gebäuden in greifbarer Nähe ist, vorausgesetzt, wir können uns in dem komplizierten Umfeld der sozialen und wirtschaftlichen Einschränkungen zurechtfinden. Auf unserem Weg nach vorn müssen wir nicht nur die technische Machbarkeit in den Vordergrund stellen, sondern auch ein Umfeld fördern, das eine rasche und wirksame Umsetzung ermöglicht und sicherstellt, dass unsere gemeinsamen Anstrengungen den Weg für eine nachhaltigere und widerstandsfähigere bebaute Umwelt ebnen. 7/111 ▪ Average GHG emissions of a multi-family house reference building can be reduced by 72% with current applicable measures (68% in embodied GHG emissions and 85% in operational GHG emissions). ▪ Decarbonization of the industry could potentially reduce the embodied emissions of a building further in the future (ca. 50%). Strategies for net-zero buildings ▪ An overall "AVOID" strategy, tackling sufficiency measures at building scale (e.g.: reduce surface per inhabitant, reduce size of buildings, undergrounds, and energy consumption) can bring down GHG emissions of a reference multi-family house by 50%. This strategy is mainly hindered by social acceptance and employment effects/economic growth feasibility indicators. ▪ The "SHIFT" strategy focuses on consistency measures to generally shift practices towards renewable sources (e.g.: biobased materials and renewable energies). The feasibility of the strategy finds high social acceptance and co-benefits but is hindered by costs and technical complexity of implementing the measures at large scale. ▪ The "IMPROVE" strategy tackles efficiency measures by improving existing practices. Partially these measures are directly applicable at building scale (e.g.: window to wall ratio, energy concept, efficiency of installations) with a limited range of GHG reduction potential. Measures concerning the framework conditions (extension of renewable energy networks and decarbonisation of the industry) have high potential to reduce GHG emissions in this strategy but are not directly applicable at building scale and rely on long-term changes happening at political level. Therefore, these measures are assessed as difficult from a costs and technical complexity point of view. Feasibility assessment ▪ Very few...

FEDRO Research Reports, Jun 2021

Nr. 623

Sicherheit des Verkehrssystems Strasse und dessen Kunstbauten Bericht Nr. 623 | Tragsicherheit de... more Sicherheit des Verkehrssystems Strasse und dessen Kunstbauten Bericht Nr. 623 | Tragsicherheit der bestehenden Kunstbauten Dezember 2009 4 Impressum Forschungsauftrag Forschungspaket AGB1: Sicherheit des Verkehrssystems Strasse u. dessen Kunstbauten Teilprojekt AGB 2005/107: Tragsicherheit der bestehenden Kunstbauten Antragsteller: Arbeitsgruppe Brückenforschung (AGB) Auftraggeber

This text summarizes the experience made with the application of a recent publication on dynamic ... more This text summarizes the experience made with the application of a recent publication on dynamic investigations of footbridges to projects in Zumaia (Bask country, Spain) and Medellín (Colombia). It also explains some important aspects when assessing dynamic behavior of 'lively' structures and reports on the execution and performance of time-history analyses.

ASTRA 569, Mar 2003

Forschungsauftrag Nr. AGB 1999/163 (93/99) auf Antrag der Arbeitsgruppe Brückenforschung März 200... more Forschungsauftrag Nr. AGB 1999/163 (93/99) auf Antrag der Arbeitsgruppe Brückenforschung März 2003 Vorwort Ausgangspunkt der vorliegenden Arbeit ist die Promotionsarbeit von Herrn Zwicky, die ihrerseits auf einer Versuchsreihe an vorfabrizierten Trägern von je über 20 m Länge beruht. Diese stammten aus dem Lehnenviadukt Wassnerwald im Kanton Uri und standen für Bruchversuche zur Verfügung. Angesichts der nach heutiger Sichtweise knappen Schubbewehrung entstand die Idee, den Schubwiderstand der Träger durch externe Vorspannung zu erhöhen. Als es auch mit den unterschiedlichsten Belastungsanordnungen nicht gelang, einen Schubbruch zu erzeugen, wurde das Thema Verstärkung obsolet und der Fokus der Arbeit verschob sich auf die integrale Beurteilung der Tragfähigkeit solcher Träger. Der Bericht folgt dem Gedankengang eines Ingenieurs, der ein bestehendes Tragwerk zu überprüfen hat. Er deckt für solche Tragwerke die Widerstandsseite des Tragsicherheitsnachweises umfassend ab und erlaubt dank der nachvollziehbaren Gedankengänge eine direkte praktische Anwendung. Durch die weitgehenden Parametrisierung der Berechnungsalgorithmen, die als Tabellenkalkulation auf der beiliegenden CD-ROM zur Verfügung stehen, sollte eine verantwortungsvolle Übertragung auf ähnlich gelagerte Fälle möglich sein. Mit dem neu erarbeiteten Wissen um den inneren Kräftefluss wird es gelingen, die Verstärkung manch bestehender Brücke zu vermeiden. Der Bezug zum konkreten Fallbeispiel "Lehnenviadukt Wassnerwald" soll die Anwendung illustrieren. Durch den Einbezug der wichtigsten Resultate der Belastungsversuche soll das Vertrauen in die vorgeschlagenen Berechnungsmethoden gefördert werden. Das Bundesamt für Strassen (ASTRA) hat auf Antrag der Arbeitsgruppe Brückenforschung die Fertigstellung dieser Arbeit durch einen grosszügigen Beitrag ermöglicht. Die Begleitkommission C der Arbeitsgruppe Brückenforschung, bestehend aus dem Vorsitzenden P. Matt und den Mitgliedern M. Donzel, H. Figi, Prof. Dr. A. Muttoni und Dr. D. Somaini, gab uns wertvolle Anregungen. Für beides möchte ich mich hiermit bedanken. Zürich, März 2003 Prof. Thomas Vogel

IBK Bericht Nr. 258, Nov 2000

Im Herbst 1996 konnten an der Steilerbachbrücke in Sufers wertvolle Erfahrungen über Feldversuche... more Im Herbst 1996 konnten an der Steilerbachbrücke in Sufers wertvolle Erfahrungen über Feldversuche an Abbruchobjekten gewonnen werden. Die in Aussicht stehenden Brückenträger des Viadukts Wassnerwald veranlassten uns, an der ETH Hönggerberg eine Anlage zu erstellen, die die Vorteile von Labor-und Feldversuchen zu kombinieren vermag.

Das Forschungsprojekt "Schubwiderstand minimal verbügelter Balken" ist Bestandteil des langfristi... more Das Forschungsprojekt "Schubwiderstand minimal verbügelter Balken" ist Bestandteil des langfristig angelegten Forschungsprogramms "Zustandsbeurteilung von Stahlbetontragwerken" am Institut für Baustatik und Konstruktion der ETH Zürich. Es wird durch das Bundesamt für Strassen des Eidgenössischen Departements für Umwelt, Verkehr, Energie und Kommunikation finanziell unterstützt. Die vorliegende Arbeit entstand auf Anregung und unter Leitung von Prof. Thomas Vogel. Ich möchte mich bei ihm herzlich bedanken für die allzeit entgegengebrachte Unterstützung, die stete Bereitschaft zur Diskussion und die grosse Freiheit, die er mir bei der Ausfertigung der Arbeit liess. Ebenfalls danken möchte ich Prof. Dr. Aurelio Muttoni für die freundliche Bereitschaft zur Übernahme des Korreferats. Mein Dank geht auch an die Arbeitskolleginnen und-kollegen am Institut für das angenehme Arbeitsumfeld. Dies gilt insbesondere für die anregenden Gespräche mit Stefan Köppel, Karel Thoma, Albin Kenel und Thomas Pfyl sowie für Tomaz Ulaga für die stete Bereitschaft zur Zusammenarbeit. Den Herren Hartwig Stempfle und Joost Meyboom möchte ich danken für die Durchsicht der Arbeit sowie der Korrektur der englischen Texte. Besonders danken möchte ich meiner Mutter Fay und meiner Freundin Silvia für den geschenkten Rückhalt und die Zuneigung während der ganzen Zeit.

SSRN Electronic Journal, 2021

Check out the Extended Abstract available for download