Nawawi Chouw | The University of Auckland (original) (raw)

Papers by Nawawi Chouw

Research paper thumbnail of Modelling of Earthquake Ground motion Spatial Variation on Uneven Sites with Varying soil condition

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Research paper thumbnail of A new way to design and construct a laminar box for studying structure-foundation-soil interaction

Earthquakes and Structures, Nov 1, 2019

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Research paper thumbnail of Assessment of relative Displacement Requirements for Bridge Girders under Current Bridge Design Regulations

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Research paper thumbnail of Seismic performance of a non-structural component with two supports in bidirectional earthquakes considering soil-structure interaction

CRC Press eBooks, Aug 25, 2017

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Research paper thumbnail of Significance of Soil-Structure Interaction and Near-Source Earthquakes in Causing Pounding of Bridge Girders

The study addresses the influence of near-source earthquakes and soil-structure interaction on th... more The study addresses the influence of near-source earthquakes and soil-structure interaction on the pounding response of two adjacent bridge frames. In the study the bridge frames and the foundations are described by a finite element method, and the subsoil by a boundary element method. The result reveals that the subsoil together with the long-period pulses in the ground motions can significantly increase the pounding potential of the structure.

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Research paper thumbnail of Prediction of the response of secondary structures under dynamic loading considering primary–secondary structure interaction

Advances in Structural Engineering, Apr 10, 2018

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Research paper thumbnail of Seismic Induced Pounding of Bridge Structures: An Overview

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Research paper thumbnail of Combined ground motion spatial variation and local site amplification effect on bridge structure responses

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Research paper thumbnail of Theoretical prediction of traffic-induced ground vibration with road filtering effect

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Research paper thumbnail of Indentation and puncture response characteristics of flax fibre-reinforced polymer pipes

Composites Part A-applied Science and Manufacturing, Aug 1, 2022

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Research paper thumbnail of The Role of Soil in Seismic Response of Bridges

Proceedings of the 8th International Conference on Civil, Structural and Transportation Engineering (ICCSTE 2023)

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Research paper thumbnail of Strain rate effect on tensile strength of glass fiber-reinforced polymers

International Journal of Modern Physics B

This study presents the tensile properties of glass fiber-reinforced polymer (GFRP) composites un... more This study presents the tensile properties of glass fiber-reinforced polymer (GFRP) composites under dynamic loadings. The dynamic tensile tests were performed via a high-speed servo-hydraulic testing machine with a velocity ranging from 1 m/s to 15 m/s, corresponding to a strain rate range between 4.9 s−1 and 93.7 s−1. The effects of the strain rate on the tensile strength and dynamic increase factor (DIF) were considered. The results showed that the tensile strength and DIF of GFRP increased with the strain rate. The failure pattern of GFRP was discussed via a group of high-speed camera images. The results of this research can provide useful information for future construction, e.g., protective structures under extreme impacts.

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Research paper thumbnail of Dynamic Splitting Tensile Behaviour of Concrete Confined by Natural Flax and Glass FRP

Polymers

Flax fibre has been used to reinforce concrete composite, but its dynamic properties have not bee... more Flax fibre has been used to reinforce concrete composite, but its dynamic properties have not been thoroughly studied. This study investigates the dynamic splitting tensile properties of plain concrete (PC) confined by flax-fibre-reinforced polymer (FFRP) and glass-fibre-reinforced polymer (GFRP). The dynamic splitting tensile tests were carried out on PC, FFRP-PC, and GFRP-PC cylinder specimens by the high-speed servo-hydraulic machine, with the impact-induced strain rates ranging from 0.1 to 58 s−1. The effect of the FRP confinement, FRP thickness and strain rate on the dynamic splitting tensile behaviour were assessed. The results indicated that similar confinement effectiveness of FFRP and GFRP is observed. The dynamic tensile strength of 1- and 2-layer FFRP-PC increased by 29% and 67%, and the one- and two-layer GFRP-PC increased by 32% and 84%, respectively. FFRP-PC and GFRP-PC cylinders showed less sensitivity to the strain rate compared with PC. The empirical relationship be...

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Research paper thumbnail of Dynamic performance of flax fiber-reinforced polymer

International Journal of Modern Physics B

The study addresses the dynamic performance of flax fiber-reinforced polymer (FFRP) composites vi... more The study addresses the dynamic performance of flax fiber-reinforced polymer (FFRP) composites via a series of drop-weight impact tests. The experiment was performed based on ASTM standards by using an instrumented falling weight impact machine. Increasing impact energy was applied on the FFRP specimens until an occurrence of perforation. The effect of composite thickness and impact striker diameter were considered. The results showed that the striker diameter and composite thickness have a significant effect on the impact properties of the composites. It is also revealed the influence factors that control the impact behavior of FFRP composite that will be useful for developing future protective fiber-reinforced composites.

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Research paper thumbnail of Influence of Excess Pore-pressure on the Seismic Response of Single and Closely Adjacent Structures on Saturated Sand

Journal of Earthquake Engineering, 2022

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Research paper thumbnail of Resilient Civil Infrastructure under Dynamic Loadings 2020

Shock and Vibration, 2021

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Research paper thumbnail of Experimental Investigation of Bridge with Footing Uplift under Near-fault Earthquake

Many investigations have confirmed the beneficial effects of footing uplift on structural perform... more Many investigations have confirmed the beneficial effects of footing uplift on structural performance, i.e. reduction of the ductility demand of structural members. Bridge piers have been designed to rock in some seismic retrofit projects, e.g. the South Rangitikei railway bridge in New Zealand. However, research on bridge with footing uplift is still limited and performed mainly numerically. Only a few experimental works on simplified single degree-of-freedom bridge models have been conducted. Another aspect that is seldom addressed is the effect of near-fault earthquake on bridge with uplift, even though destructive damage to bridges has been observed in the near-source regions. In this study the response of a single-span model bridge with uplift due to simultaneous vertical and horizontal excitations is investigated using a shake table. Artificial plastic hinges are constructed to replicate the nonlinear behaviour of the bridge piers. The excitations are selected from ground moti...

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Research paper thumbnail of Evaluation of the adequacy of a spring‐mass model in analyses of liquid sloshing in anchored storage tanks

Earthquake Engineering & Structural Dynamics, 2021

This research addresses the influence of the load characteristics, that is, frequency content and... more This research addresses the influence of the load characteristics, that is, frequency content and maximum acceleration, on the wall stresses of an anchored water storage tank. A low‐density polyethylene tank with a range of six different aspect ratios (water height to tank radius) was tested using a shake table. Eight sine excitations that cover the lowest free vibration frequency of the tank‐water system were applied. Additionally, two sets of five Ricker wavelet excitations were utilized. Each set represents potential earthquakes with a bandwidth between a low and a high dominant frequency. The experimentally determined maximum stresses and those obtained from calculations using a common spring‐mass model employed for seismic analysis of tanks were compared. The results reveal that the relationship between the excitation frequency and the wall stresses strongly depends on the sloshing behavior, especially when the frequency of loading is in the vicinity of the lowest free–vibration frequency of the tank–water system. When the frequencies are dissimilar, there is a proportional relationship between stress and the maximum acceleration of the excitation. The spring‐mass model was found to underestimate both the maximum hoop stress (for aspect ratios greater than two) and axial stress (for aspect ratios equal to 0.5). This occurs because is the spring‐mass model cannot capture, in all cases, the contribution of chaotic sloshing to wall stress.

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Research paper thumbnail of Dynamic response of stand-alone and adjacent footing on saturated sand

Soil Dynamics and Earthquake Engineering, 2021

Abstract This paper presents results from geotechnical centrifuge tests performed at the Japanese... more Abstract This paper presents results from geotechnical centrifuge tests performed at the Japanese Institute of Occupational Safety and Health (JNIOSH) in Tokyo, Japan. A range of shallow footing configurations with different bearing pressures founded on saturated sand in a laminar box on a shake table was studied using harmonic excitations. The free-field condition was also studied as a reference. The study aimed to address the influence of stand-alone and closely adjacent shallow foundations on the dynamic response of the soil-foundation-structure system. A partially drained response of the soil and a minor dilative response for large values of shear strain were observed for the free-field case. In the case with footings, the settlement was found to be largely due to the footing penetrating the supporting sand. A dilative response of the soil beneath the footings was observed for the stand-alone configurations at the beginning of the base motions, this was not observed in the case of adjacent footings. Adjacent footings also tilt inwards consistently while stand-alone footings did not present a clear tilt pattern. In terms of the acceleration recorded in the near-surface soil beneath the footings, a reduction was observed after a few cycles in the free-field case. This reduction was considerably smaller in the case with footings with no significant differences between the response of the stand-alone and that of the closely adjacent footings.

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Research paper thumbnail of Impact of Seismic Uplift and Soil Support on the Acceleration Distribution of a Liquid Storage Tank

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015), 2019

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Research paper thumbnail of Modelling of Earthquake Ground motion Spatial Variation on Uneven Sites with Varying soil condition

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A new way to design and construct a laminar box for studying structure-foundation-soil interaction

Earthquakes and Structures, Nov 1, 2019

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Research paper thumbnail of Assessment of relative Displacement Requirements for Bridge Girders under Current Bridge Design Regulations

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Seismic performance of a non-structural component with two supports in bidirectional earthquakes considering soil-structure interaction

CRC Press eBooks, Aug 25, 2017

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Significance of Soil-Structure Interaction and Near-Source Earthquakes in Causing Pounding of Bridge Girders

The study addresses the influence of near-source earthquakes and soil-structure interaction on th... more The study addresses the influence of near-source earthquakes and soil-structure interaction on the pounding response of two adjacent bridge frames. In the study the bridge frames and the foundations are described by a finite element method, and the subsoil by a boundary element method. The result reveals that the subsoil together with the long-period pulses in the ground motions can significantly increase the pounding potential of the structure.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Prediction of the response of secondary structures under dynamic loading considering primary–secondary structure interaction

Advances in Structural Engineering, Apr 10, 2018

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Seismic Induced Pounding of Bridge Structures: An Overview

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Combined ground motion spatial variation and local site amplification effect on bridge structure responses

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Theoretical prediction of traffic-induced ground vibration with road filtering effect

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Indentation and puncture response characteristics of flax fibre-reinforced polymer pipes

Composites Part A-applied Science and Manufacturing, Aug 1, 2022

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Role of Soil in Seismic Response of Bridges

Proceedings of the 8th International Conference on Civil, Structural and Transportation Engineering (ICCSTE 2023)

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Strain rate effect on tensile strength of glass fiber-reinforced polymers

International Journal of Modern Physics B

This study presents the tensile properties of glass fiber-reinforced polymer (GFRP) composites un... more This study presents the tensile properties of glass fiber-reinforced polymer (GFRP) composites under dynamic loadings. The dynamic tensile tests were performed via a high-speed servo-hydraulic testing machine with a velocity ranging from 1 m/s to 15 m/s, corresponding to a strain rate range between 4.9 s−1 and 93.7 s−1. The effects of the strain rate on the tensile strength and dynamic increase factor (DIF) were considered. The results showed that the tensile strength and DIF of GFRP increased with the strain rate. The failure pattern of GFRP was discussed via a group of high-speed camera images. The results of this research can provide useful information for future construction, e.g., protective structures under extreme impacts.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dynamic Splitting Tensile Behaviour of Concrete Confined by Natural Flax and Glass FRP

Polymers

Flax fibre has been used to reinforce concrete composite, but its dynamic properties have not bee... more Flax fibre has been used to reinforce concrete composite, but its dynamic properties have not been thoroughly studied. This study investigates the dynamic splitting tensile properties of plain concrete (PC) confined by flax-fibre-reinforced polymer (FFRP) and glass-fibre-reinforced polymer (GFRP). The dynamic splitting tensile tests were carried out on PC, FFRP-PC, and GFRP-PC cylinder specimens by the high-speed servo-hydraulic machine, with the impact-induced strain rates ranging from 0.1 to 58 s−1. The effect of the FRP confinement, FRP thickness and strain rate on the dynamic splitting tensile behaviour were assessed. The results indicated that similar confinement effectiveness of FFRP and GFRP is observed. The dynamic tensile strength of 1- and 2-layer FFRP-PC increased by 29% and 67%, and the one- and two-layer GFRP-PC increased by 32% and 84%, respectively. FFRP-PC and GFRP-PC cylinders showed less sensitivity to the strain rate compared with PC. The empirical relationship be...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dynamic performance of flax fiber-reinforced polymer

International Journal of Modern Physics B

The study addresses the dynamic performance of flax fiber-reinforced polymer (FFRP) composites vi... more The study addresses the dynamic performance of flax fiber-reinforced polymer (FFRP) composites via a series of drop-weight impact tests. The experiment was performed based on ASTM standards by using an instrumented falling weight impact machine. Increasing impact energy was applied on the FFRP specimens until an occurrence of perforation. The effect of composite thickness and impact striker diameter were considered. The results showed that the striker diameter and composite thickness have a significant effect on the impact properties of the composites. It is also revealed the influence factors that control the impact behavior of FFRP composite that will be useful for developing future protective fiber-reinforced composites.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Influence of Excess Pore-pressure on the Seismic Response of Single and Closely Adjacent Structures on Saturated Sand

Journal of Earthquake Engineering, 2022

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Resilient Civil Infrastructure under Dynamic Loadings 2020

Shock and Vibration, 2021

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Experimental Investigation of Bridge with Footing Uplift under Near-fault Earthquake

Many investigations have confirmed the beneficial effects of footing uplift on structural perform... more Many investigations have confirmed the beneficial effects of footing uplift on structural performance, i.e. reduction of the ductility demand of structural members. Bridge piers have been designed to rock in some seismic retrofit projects, e.g. the South Rangitikei railway bridge in New Zealand. However, research on bridge with footing uplift is still limited and performed mainly numerically. Only a few experimental works on simplified single degree-of-freedom bridge models have been conducted. Another aspect that is seldom addressed is the effect of near-fault earthquake on bridge with uplift, even though destructive damage to bridges has been observed in the near-source regions. In this study the response of a single-span model bridge with uplift due to simultaneous vertical and horizontal excitations is investigated using a shake table. Artificial plastic hinges are constructed to replicate the nonlinear behaviour of the bridge piers. The excitations are selected from ground moti...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Evaluation of the adequacy of a spring‐mass model in analyses of liquid sloshing in anchored storage tanks

Earthquake Engineering & Structural Dynamics, 2021

This research addresses the influence of the load characteristics, that is, frequency content and... more This research addresses the influence of the load characteristics, that is, frequency content and maximum acceleration, on the wall stresses of an anchored water storage tank. A low‐density polyethylene tank with a range of six different aspect ratios (water height to tank radius) was tested using a shake table. Eight sine excitations that cover the lowest free vibration frequency of the tank‐water system were applied. Additionally, two sets of five Ricker wavelet excitations were utilized. Each set represents potential earthquakes with a bandwidth between a low and a high dominant frequency. The experimentally determined maximum stresses and those obtained from calculations using a common spring‐mass model employed for seismic analysis of tanks were compared. The results reveal that the relationship between the excitation frequency and the wall stresses strongly depends on the sloshing behavior, especially when the frequency of loading is in the vicinity of the lowest free–vibration frequency of the tank–water system. When the frequencies are dissimilar, there is a proportional relationship between stress and the maximum acceleration of the excitation. The spring‐mass model was found to underestimate both the maximum hoop stress (for aspect ratios greater than two) and axial stress (for aspect ratios equal to 0.5). This occurs because is the spring‐mass model cannot capture, in all cases, the contribution of chaotic sloshing to wall stress.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dynamic response of stand-alone and adjacent footing on saturated sand

Soil Dynamics and Earthquake Engineering, 2021

Abstract This paper presents results from geotechnical centrifuge tests performed at the Japanese... more Abstract This paper presents results from geotechnical centrifuge tests performed at the Japanese Institute of Occupational Safety and Health (JNIOSH) in Tokyo, Japan. A range of shallow footing configurations with different bearing pressures founded on saturated sand in a laminar box on a shake table was studied using harmonic excitations. The free-field condition was also studied as a reference. The study aimed to address the influence of stand-alone and closely adjacent shallow foundations on the dynamic response of the soil-foundation-structure system. A partially drained response of the soil and a minor dilative response for large values of shear strain were observed for the free-field case. In the case with footings, the settlement was found to be largely due to the footing penetrating the supporting sand. A dilative response of the soil beneath the footings was observed for the stand-alone configurations at the beginning of the base motions, this was not observed in the case of adjacent footings. Adjacent footings also tilt inwards consistently while stand-alone footings did not present a clear tilt pattern. In terms of the acceleration recorded in the near-surface soil beneath the footings, a reduction was observed after a few cycles in the free-field case. This reduction was considerably smaller in the case with footings with no significant differences between the response of the stand-alone and that of the closely adjacent footings.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Impact of Seismic Uplift and Soil Support on the Acceleration Distribution of a Liquid Storage Tank

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015), 2019

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Research paper thumbnail of Dynamics of bridge structures

Elsevier, 2016

Innovative Bridge Design Handbook

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