A study on Strengthening of Building foundation for Storey Extension (original) (raw)
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A study on Strengthening of Building foundation for Storey Extension.pdf
2019
Storey extensions are an increasingly popular way to crowded cities. Lack experience and knowledge concerning strengthening of structures are major challenges for engineers. This paper presents strengthening practice adopted for foundations of existing building when storey extension is needed. Literature concerning strengthening techniques commonly adopted and some historical cases were reviewed. A complex hall building in university of Khartoum which was rehabilitated in 2009 by strengthening the structural members of the existing building to accommodate additional floors was undertaken as a case study. The records and reports of the original design and last rehabilitation of the building were reviewed. Field inspection of the building condition before rehabilitation was carried out. The study results showed that the appropriate design, the strengthening materials used and the procedure followed are the key factors for economical and successful strengthening.
Advancements in Civil Engineering & Technology, 2019
Saudi Arabia's kingdom is not free from seismic tremors. It has encountered numerous quakes amid the ongoing history, and the past investigations on this field exhibited this contention. Many existing structures in Abha City have not been intended to oppose seismic forces. Moreover, it is imperative to contemplate the reaction of these structures under seismic conditions. Likewise, there is a lack in the examinations done in this field identified with Abha City. Consequently, existing structures ought to be assessed with respect to their ability for opposing expected seismic impacts before recovery works. Investigation was completed by utilizing auxiliary examination program (SAP2000) [1] with the utilization of static technique proposed by the Saudi Building Code (SBC) [2] to decide the reaction of regular multi-storey structures made of strengthened cement because of quake ground loads. Objective of this paper is to assess the execution of existing multi-storey RC working in Abha City under seismic loads. To accomplish this goal, a 3D model for eight-storey RC building was developed utilizing SAP2000 examination program, though tremor loads were determined by static technique. Outcomes got from this paper inferred that the present plan of existing structures in Abha city is dangerous for the present seismicity of Abha territory. At last, it has been verified that RC shear walls signified a truly reasonable procedure, as a fortifying method for existing RC structures, to lessen the seismic defenselessness of these structures.
The chamber of Civil Engineers in Northern Cyprus began to approve building projects in 1981. Until that time, such projects were designed according to the rules of the Streets and Buildings Regulations (Cap 96). By the new revisions of these building rules and regulations of 1981, buildings which are higher than four storeys were asked to make an earthquake analysis to ascertain if they are able to resist earthquake force. In 1993, new revisions were made and some practical precautions were taken for better solutions and quality of the projects then. If shear walls are placed in two different directions at 1 % of the total floor area of a building, then earthquake analysis will not be required. Since there is a building stock that was constructed without this earthquake analysis, and their performances are not well known, earthquake performances of these buildings are analysed. The buildings found to be earthquake prone are strengthened by application of suitable strengthening method. Presently, there are needs to improve the economy of strengthening method application to ensure that the cost of strengthening does not exceed the cost of raising a new building. Therefore, in this study, a real life building apartment is selected from the building stock constructed in 1970 in Famagusta, Cyprus. It is modeled using structural software. The performance assessment is obtained. According to these results, most available strengthening methods in this region are compared. A direct real cost of the strengthening materials are considered. The economy of the materials required for the strengthening application is obtained. Such methods will serve its purpose on the building bearing load capacity, with respect to the economy of the applied strengthening methods. The best method is recommended considering the economy and problems found during the performance check for the building investigated.
Strengthening Technique of Reinforce Concrete Structure: Bangladesh Perspective
Problem Statement: Strengthening of existing building is significant issue when need to carry additional load. Section Enlargement, RC jacketing and retrofitting by FRP are common strengthening methods used by practical engineers in Bangladesh to increase the load carrying capacity of an existing building. The aim of the study was to determine the most effective and economical strengthening methods among the mentioned methods in perspective of Bangladesh for one storey vertical extension. Approach: Methodology of the study included, making plan and beam-column layout, capacity assessment, determination of allowable bearing capacity of soil, structural analysis and cost analysis. The actual compressive strength of concrete was determined by core test. Results: After the analyses, results show that the column and foundation merely carry the load from super structure. But, the column and foundation is not capable of carrying extra load from additional storey as the design vertical load for four storeys will exceeds the load carrying capacity of the element and hence, strengthening is required for column and foundation which will prone to damage after vertical extension. Conclusions: Finally, strengthening of column by RCC jacketing and strengthening of foundation by foundation enlargement were selected by cost analysis and engineering point of view.
Many RC structures are influenced by different adverse conditions, where the serviceability and structural capacity may be decreased. Some structural disorders may be observed due to inadequacy of reinforcement provided, strength of concrete or the difference in grade of concrete used during construction. This requires the application of strengthening measures. Hence the structure is thoroughly investigated for quality, strength of concrete and other design aspects. A major part of the investigation also involves the feasibility of one additional floor over the existing RC structure where the deficiency of reinforcement is analyzed for the proposed additional load. The appropriate strengthening measures for the deficient RC members are presented based on the analysis of the structure and also considering the different site constraints.
Case Study: The Strengthening and Rehabilitation of a School Building with Poor Construction Quality
IOP Conference Series: Materials Science and Engineering
Old infrastructure in most small islands developing states were built with poor construction quality leading to reduced concrete strength and load changes in these buildings are very common. Consequently, these structures have shown signs of premature damages and their service life remain elusive. This article deals with the inspection, assessment and strengthening of a reinforced concrete building, in Mauritius that is currently being used as a public school. The building was built in the year two thousands and is two storeys high. The establishment wants to add an additional storey on the existing building to increase student population. However, the building is showing signs of distress resulted from poor construction quality. The columns are misaligned on all three levels and the slab thickness is inadequate causing excessive vibration on the floors. The managements are not in favour of pulling down the existing building as they will have to abide by the new building regulations which will consequently decrease the allowable buildable area and will cause major disruption to the day to day activities. Therefore, the most feasible solution is to strengthen the load carrying capacity of members which have become structurally deficient over time to make the building safe and adopt to the addition of one storey above the existing building.
Reconstruction of an existing building with one additional storey
2019
This study intends to analyze possible constructive solutions applied when adding more floors to the existing buildings. The objective was to design the best applicable storey-adding structure, scenarios when strengthening scheme is adopted or not being considered. The work was commissioned by AlfaGasStroy-Servis LLC. In the study, the emphasis is on the jacket type storey-adding technique when the portal frames on independent foundations are erected around the existing building. The frames joined together to form a structure that bears the load from the superstructure being built. Solutions with reinforced concrete, steel, and timber frame are discussed. In addition, the question of an effective floor system that can be used in the reconstruction is considered. The estimates are based on existing scientific researches and developments. Calculations are carried out by means of special software using data obtained from the previous designs of the existing building. As a result of this thesis, it is deduced that the load-bearing performance is weak to withstand the weight of additional structures. The extra storey in the form of a self-bearing system is designed. Materials are chosen considering their effectiveness and construction site conditions, cross-sections of the elements are selected.
2013
The challenges posed in the choice selection of strengthening methods to strengthen old existing buildings which might be exposed to external loads, poor concrete grade, poor construction and review in codes has been of concern recently. Through the various guidelines for building evaluation, strengthening and with innovative structural codes for design, building assessment and strengthening are carried out using newly developed technologies worldwide. Basically, there are two major categories of strengthening; local and global methods. Local method is focused at the element level on structural members which are deficient and need improvement to perform better. This method includes adding composites, concrete or steel on the surface of a structural member. They are all effective but also have their disadvantages, while the global method acts on the structural level. Its application will lead to obtaining the behavior of the entire structure. This method consists of addition of steel bracings, shear walls and infill walls. These methods equally have their effectiveness and disadvantages. In this study, strengthening methods were discussed considering its advantages and disadvantages where some application procedures were as well highlighted. The procedures for building assessment were also discussed. A coded decision selection program for strengthening methods were constructed which will help for selecting the best option from strengthening methods. Coded strengthening programs for fiber reinforced polymer (FRP) were also prepared and it gave the same result with the referenced FRP strengthening. Two case studies were carried out in other to compare iv the result with the coded decision selection tool. The cases studies were modeled and designed with structural software such as STA4CAD, CSi COL and Engissol structural software. The selection tool and the case studies gave the same result for the strengthening option. Both have shown that shear wall strengthening is the best option for strengthening the two investigated buildings. The economic evaluation of the materials used in different strengthening method studied, has shown that, shear wall is the least in the cost of strengthening. Therefore, shear wall strengthening method is cheaper, efficient and has significantly contributed to the overall strengthening and improvement of the performance of the considered building.
A STUDY OF SEISMIC STRENGTHENING OF MULTI STOREY BUILDING
Concepts Books Publication, 2015
Earthquakes, even though they occur rarely, induce inertia force which is dynamic and complex. Moreover, they are sometimes so devastating that it is worth going into the depth of understanding them. The current work is one step towards understanding the complex effects of this dynamic force particularly on low rise RC structures which are found in almost all parts of the world. During 2001 Bhuj earthquake of India, a major damage was observed in RC framed structures at Ahemdabad which were in the range of G+3 to G+7 storey. Most of the buildings were having a normal grid of 3m x 3m column spacing with a storey height of 3m. Hence the present work, which is expected to act as a guide line for Civil and Structural Engineers in smaller towns and cities where expert advice may not be easily available, is devoted to RC framed structures ranging from G+3 to G+ 7 storeys. Out of the various factors affecting the earthquake and dynamic response of RC framed structures, in the current study, the shape of the column is considered to be one of the factors. The G+7 storey frame without the consideration of brick infill is subjected to push over analysis. The performance point for rectangular and equivalent square shaped cross section of columns is studied. The study incorporates two variations in the overall plan dimensions - 6m x 6m and 6m x 9m having four panes each of 3m x 3m and 3m x 4.5m respectively. The same set of models are also studied with brick infill walls modeled as 2D finite elements and equivalent strut. The performance point obtained from the push over analysis is considered as a measure of performance. Parameters like base shear, roof displacement, number of plastic hinges, severity of hinges, effective damping, etc. are compared for the mathematical models at performance point.