Gopal Madabhushi

Gopal Madabhushi
University of Cambridge | Cam · Department of Engineering

Doctor of Philosophy

About

319
Publications
107,252
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5,741
Citations
Citations since 2016
137 Research Items
3792 Citations
20162017201820192020202120220200400600
20162017201820192020202120220200400600
20162017201820192020202120220200400600
20162017201820192020202120220200400600
Introduction
Skills and Expertise

Publications

Publications (319)
Article
Saturated deposits of loose sand may suffer liquefaction under earthquake shaking. Liquefaction-induced damage occurs during the earthquake loading and may continue during the post-liquefaction reconsolidation stage in which excess pore pressures gradually dissipate. An accurate evaluation of soil parameters is of great significance for the full de...
Article
Full-text available
Deep excavations in over-consolidated clays lead to swelling of the clay, which can exert large swell pressures on the basement slabs. In this paper, four prototype scenarios of basement construction in over-consolidated clay were investigated using both centrifuge modelling and finite element modelling. The main aim was to discern the effects of t...
Conference Paper
Full-text available
Centrifuge modelling is a widely-used tool to assess the response of reduced-scale structures subjected to earthquakes under an increased gravity environment. Indeed, this experimental technique allows the user to obtain experimental results under repeatable and controlled conditions. However, space limitations force the model to be constrained int...
Conference Paper
Offshore wind is an abundant and indispensable source of renewable energy which recently has seen rapid expansion in East Asia and North America. Soil profiles in East Asia can typically include shallow layers of loose, liquefiable sand overlying competent soil strata which may impact the stability of both the foundation and the scour protection du...
Article
Long-term heave of basement slabs is a significant problem in cities with over-consolidated clay, such as London. There is a dearth of data to calibrate the methods commonly used by designers to predict heave displacement and swell pressure. This paper presents results from two centrifuge tests aimed at reproducing the phenomenon of long-term basem...
Article
Full-text available
This paper presents the experimental results and analysis from two centrifuge experiments that simulated the seismic response of a gentle slope in soft clay. The two models consisted of a three-degree and a six-degree slope in soft clay, respectively, which are representative of typical slopes found on marine seabeds on the continental margins. The...
Article
Wind turbine structures can be susceptible to damage from earthquake loading due to large overturning moments at the foundation level. As the wind energy market expands to seismically active parts of the world, it becomes important to evaluate the seismic behaviour of these structures. Especially, earthquake-induced liquefaction can be important wh...
Article
This paper reports the results of a series of centrifuge experiments exploring the dynamic response of pile foundations. The model tested in a centrifuge at 50g consisted of an isolated pile and two pile groups embedded in a kaolin clay, subjected to a sequence of quasi-sinusoidal waves with different amplitudes and frequencies. The results are bac...
Article
Full-text available
Allowing the transitory attainment of bearing capacity of caisson foundations supporting bridge piers during strong seismic events can lead to substantial optimisation in their design and major cost savings. If the approach of Capacity Design is applied to geotechnical systems, the temporary triggering of plastic mechanisms may be permitted if the...
Presentation
Full-text available
Over the last 20 years, the growing interest in renewable energies has been boosting research on wind turbines, both onshore and offshore. Although their design is mainly ruled by either the aero or hydro-dynamic loads, the latest development of wind turbine farms in seismic-prone areas, such as East Asia and the Californian coast, has increased th...
Conference Paper
Full-text available
Seismic performance of caisson foundations supporting bridge piers may take advantage of soil inelastic response when subjected to strong seismic events, thanks to the soil nonlinear and hysteretic behaviour. This can bring to a substantial optimisation in caisson design and major cost savings. In the framework of Capacity Design extended to geotec...
Conference Paper
As the world is working towards accelerating the global transition to clean power, the development of floating offshore wind turbine (FOWT) technologies is becoming increasingly important. The design of robust anchors that can sustain severe cyclic loads from the wind, waves and currents, for a large number of cycles, is central to the deployment o...
Article
A round-robin centrifuge model test for an identical saturated sloping deposit with various initial conditions was conducted in the framework of liquefaction experiments and analysis project (LEAP) with 10 international institutes. To pursue two main objectives: (1) the validation of the generalized scaling law (GSL); and, (2) the development of ad...
Article
Construction of retaining walls in urban areas is necessary to maintain the safety of the surrounding structures during the excavation for new structures. However, the additional loading from the existing structures can result in a higher seismic vulnerability of retaining walls and therefore leads to an increased risk to the structures. As a resul...
Article
Full-text available
Centrifuge modelling is an effective tool to assess the response of reduced-scale structures subjected to earthquakes under increased gravity. Space limitations, however, force the model to be contained within relatively small boxes, whose boundaries may affect the seismic performance of the structure under consideration. In this paper, the influen...
Article
A generalized shear-lag theory for fibres with variable radius is developed to analyse elastic fibre/matrix stress transfer. The theory accounts for the reinforcement of biological composites, such as soft tissue and bone tissue, as well as for the reinforcement of technical composite materials, such as fibre-reinforced polymers (FRP). The original...
Article
Full-text available
In this study, the suitability of the pseudostatic approach for the seismic analysis of pile foundations in layered soils is explored by means of experimental data from centrifuge tests performed at 60g. A free-head single pile and a capped (1 × 3) pile group, embedded in a two-layered soil comprising a soft clay layer underlain by dense sand, are...
Article
A series of geotechnical centrifuge tests to investigate the long-term heave behavior of basements in over-consolidated clay was performed, and the profiles of the slab displacement and underslab pressure were measured simultaneously. The same prototypes were simulated using Plaxis 2D with the clay stratum represented by the small-strain hardening...
Conference Paper
Full-text available
Consideration of the instantaneous bearing capacity of caisson foundations supporting bridge piers and subjected to strong ground motions can lead to a substantial optimisation in caisson design and major cost savings. In the framework of the newly-emerging paradigm of Capacity Design extended to geotechnical systems, temporary attainment of limit...
Article
The original paper described an effective stress-based methodology developed for the prediction of earthquake-induced ground surface settlement of partially saturated sand deposits with occluded air bubbles. A discussion was submitted in response to this study. The writers sincerely appreciate the discussers' interest in this research and their val...
Conference Paper
Full-text available
This paper presents experimental data from two series of centrifuge tests on pile foundations embedded in a kaolin clay under earthquake excitation. A single pile and two pile-group configurations were tested in the centrifuge at 50g. In the first test series (flight 1) the seismic response of the soil-pile system was monitored, allowing experiment...
Article
Full-text available
This article presents a model preparation methodology for simulating the seismic behavior of a gentle slope in clay with the presence of a soft, weak layer employing centrifuge testing. The model consisted of a three-layered slope of relatively soft clay with a 3°inclination, representative of Brazilian marine subsoils. In-flight characterization o...
Article
Full-text available
Allowing structures to rock during an earthquake can effectively provide base isolation at a relatively small cost. Rocking limits the base shear demand and provides self‐centering, but the rocking response depends on energy dissipation caused by interaction with the soil and impacts during re‐centering. This paper addresses the computational model...
Chapter
Full-text available
Long-term basement heave is a pertinent problem in the construction of underground spaces in over-consolidated clay strata, notably the clays of southeastern England. When a basement is constructed, the permanent removal of soil above formation level inevitably causes upward movement of the remaining soil, or heave pressures on the base slab. In ov...
Article
Full-text available
Soil liquefaction can cause excessive damage to structures as witnessed in many recent earthquakes. The damage to small/medium-sized buildings can lead to excessive death toll and economic losses due to the sheer number of such buildings. Economic and sustainable methods to mitigate liquefaction damage to such buildings are therefore required. In t...
Chapter
Countermeasure techniques against earthquake-induced liquefaction aim to mitigate damage on infrastructures. Vertical drains performance has been evaluated during the last decades showing effectiveness in the reduction of structural damage. The performance of alternative drain arrangements considering the influence of existing buildings have been r...
Chapter
Earthquake-induced liquefaction causes extensive damage to infrastructure. Soil liquefaction-induced effects can account for a significant proportion of damage such as the settlement of existing buildings on liquefiable soils. The influence of structures on the behavior of liquefiable soil is complex. In this paper, the effect of bearing pressure o...
Article
Full-text available
Annular shaped pile groups are a very common foundation layout for onshore wind turbines and other slender structures. In this study, their performance under vertical loads of moderate to high eccentricity, including moment rotation response and bearing capacity, was investigated by centrifuge testing on small scale physical models embedded in kaol...
Article
It is not uncommon for buildings requiring good seismic performance, with objectives of immediate occupancy and continuous operation, to be equipped with supplemental damping devices. Oil dampers are a popular type of velocity-dependant devices that can be fitted into a structure without incurring considerable changes to the frame stiffness. Semina...
Article
This research investigates the influence of pile spacing on the dynamic behavior of pile groups by performing a series of specifically designed dynamic centrifuge experiments on pile foundations embedded in a two-layered soil profile. A single pile and two 3 × 1 row pile groups with different pile spacing were used as model pile foundations, and th...
Book
This book comprises the proceedings of the 1st International Symposium on Construction Resources for Environmentally Sustainable Technologies. The contents of this volume focus on issues related to natural and man-made disasters, and discuss solutions through the use of alternative resources, towards building a sustainable and resilient society fro...
Conference Paper
p>Monitoring bridges for precursors of failure has the potential to improve their safety and resilience. However, the most prominent cause of bridge failure, scour, is difficult to monitor as it occurs underwater. The potential to identify scour by monitoring changes in the natural frequencies of a bridge is studied experimentally in this research....
Article
Full-text available
In an urban environment, it is often necessary to locate structures close to existing retaining walls due to congestion in space. When such structures are in seismically active zones, the dynamic loading attracted by the retaining wall can increase. In a novel approach taken in this paper, finite element-based numerical analyses are presented for t...
Article
Full-text available
The original paper described an effective stress-based methodology developed for the prediction of earthquake-induced ground surface settlement of partially saturated sand deposits with occluded air bubbles. A discussion was submitted in response to this study. The writers sincerely appreciate the discussers' interest in this research and their val...
Preprint
This research investigates the influence of pile spacing on the dynamic behaviour of pile groups by performing a series of specifically designed dynamic centrifuge experiments on pile foundations embedded in a two-layered soil profile. A single pile and two 3 × 1 row pile groups with different pile spacing were used as model pile foundations, and t...
Article
Full-text available
One of the most prevalent causes of bridge failure around the world is “scour” – the gradual erosion of soil around a bridge foundation due to fast-flowing water. A reliable technique for monitoring scour would help bridge engineers take timely countermeasures to safeguard against failure. Although vibration-based techniques for monitoring structur...
Article
Full-text available
Monopiles and gravity base foundations (GBF) are two of the most commonly used foundations for offshore wind turbines. As resonance can cause damage and even failure of wind turbines, understanding the difference between the dynamic responses of monopiles and GBFs under free vibration is important. However there is little experimental data regardin...
Article
Aquifer thermal energy storage systems allow the storage of excess heat from summer for use during the winter. This investigation looks at the suitability of a small scale experimental model as a method for simulating the behaviour of full-scale unconfined aquifers for thermal storage. Thermal energy was stored via the injection of 40, 60 and 80 ◦...
Article
A series of dynamic centrifuge experiments was conducted on model pile foundations embedded in a two-layered soil profile consisted of soft-clay layer underlain by dense sand. These experiments were specifically designed to investigate the individual effect of kinematic and inertial loads on a single pile and a 3×1 row pile group during model earth...
Conference Paper
Development of offshore wind farms in seismic zones requires consideration of monopile foundation design subjected to dynamic earthquake-induced loads. This paper presents the results of a dynamic centrifuge test, investigating the monopile response to seismic loads in dry cohesionless soils. The test involved two identical instrumented monopiles,...
Article
Full-text available
In the event of earthquake-induced liquefaction, structures with shallow foundations can suffer excessive settlement and rotation. In this paper, the rotational response of structures with shallow foundations resting on liquefiable layers with thickness equal to or smaller than the width of the foundation is examined through a series of dynamic cen...
Article
Gravity wharf (GW) structures are gaining popularity in new port constructions, as well as expanding existing ports. When such structures are located on saturated alluvial seabed, their seismic performance needs to be established, particularly from a liquefaction point of view. In this paper, time domain finite element (FE) analyses were carried ou...
Article
There is an increasing tendency for buildings in urban areas to have basements. However, the coseismic behavior of these structures is not well understood. Dynamic centrifuge experiments were performed to investigate the behavior of structures with narrow basements located in liquefiable soils. The tests showed that basements can be used to reduce...
Poster
Full-text available
A centrifuge testing programme established natural frequency sensitivity to different forms of scour at the foundations of different types of bridges. Significant frequency sensitivity (up to 44%) detected in this experiment demonstrates the potential for using natural frequency as an indicator of bridge scour.
Article
Earthquake-induced liquefaction of soils can result in floatation failure of lightweight buried structures such as tunnels, with the potential for economic and human loss. Ground improvement around a tunnel is one approach to preventing this mode of failure. Four 1-g shaking table tests have been conducted including a reference test with a tunnel i...
Article
Full-text available
This research provides an insight into the previously unexplored aspects of kinematic pile bending, especially for large intensity earthquakes where the soil behaviour is highly non-linear. In this study, a series of dynamic centrifuge experiments was conducted on pile foundations embedded in a two-layered soil profile to investigate the kinematic...
Article
Full-text available
Induced partial saturation is an innovative soil improvement technique intended to mitigate earthquake-induced liquefaction. Historical records indicate that successive earthquakes may occur in high seismic areas. Therefore, a comprehensive understanding of the response of partially saturated soils to sequential ground motions is of great significa...
Article
Full-text available
The paper presents a state-of-the-art review of the current understanding of the seismic behaviour of tunnels. Emphasis is placed on recorded responses of actual tunnels during past earthquakes, as well as relevant experimental studies. In particular, the observed seismic performance of tunnels is initially discussed, by providing cases of reported...
Article
Experimental research into the seismic performance of buildings with passive oil dampers has so far been restricted to large‐scale testing of frames erected on laboratory shaking tables that ignore the foundation soil below. This simplification of the problem falls short of replicating dynamic soil‐structure interaction that would occur in the fiel...
Chapter
Full-text available
As part of the LEAP project the seismic response of a liquefiable 5° slope was modelled at a number of centrifuges around the world. In this paper the two experiments conducted at Cambridge University are discussed. The model preparation is detailed with particular emphasis on the sand pouring, saturation and slope cutting process. The presence of...
Technical Report
Full-text available
The use of tactile pressure sensing mats has been gaining popularity among geotechnical centrifuge modellers. Tactile sensing systems such as Tekscan allow experimenters to obtain profiles of soil-structure contact pressures and visualise the results. This report builds upon previous work on the calibration of such pressure mats and describes how t...
Article
Reducing the risk of structural damage due to earthquake-induced liquefaction in new and existing buildings is a challenging problem in geotechnical engineering. Drainage countermeasure techniques against liquefaction have been studied over the last decades with an emphasis on the use of vertical drains. This technique aims to allow a rapid dissipa...
Article
Full-text available
Several techniques have been developed in order to mitigate damage to buildings during and after liquefaction events. Benefits of using vertical drains have been verified by analysing their performance in the soil and evaluating their effectiveness in dissipation of excess pore pressures generated by the earthquake. However, the effect of drains in...
Chapter
The experimental results of LEAP (Liquefaction Experiments and Analysis Projects) centrifuge test replicas of a saturated sloping deposit are used to assess the sensitivity of soil accelerations to variability in input motion and soil deposition. A difference metric is used to quantify the dissimilarities between recorded acceleration time historie...
Chapter
Full-text available
This paper presents comparisons of 11 sets of Type-B numerical simulations with the results of a selected set of centrifuge tests conducted in the LEAP-2017 project. Time histories of accelerations, excess pore water pressures, and lateral displacement of the ground surface are compared to the results of nine centrifuge tests. A number of numerical...
Chapter
This paper compares experimental results from every facility for LEAP-UCD-2017. The specified experiment consisted of a submerged medium-dense clean sand with a 5-degree slope subjected to 1 Hz ramped sine wave base motion in a rigid container. The ground motions and soil density were intentionally varied from experiment to experiment in hopes of d...
Chapter
Full-text available
This paper describes the specifications developed by and distributed to all of the centrifuge test facilities involved in LEAP-UCD-2017. The specified experiment consisted of a submerged medium dense clean sand with a 5-degree slope subjected to 1 Hz ramped sine wave base motion in a rigid container. This document describes the detailed geometry, s...
Conference Paper
The large diameter monopile is a commonly used foundation concept for offshore wind turbines. The advantages of geometrical simplicity and reliable performance make it often the most attractive solution. Despite the concept’s high popularity, optimisation of the current design models can still be made. To address fundamental understanding of modell...
Article
Full-text available
Partially saturated soils associated with the presence of occluded air bubbles are commonly encountered in seismically active zones. Yet, there is a lack of deep understanding of the mechanisms of settlement that partially saturated soils suffer during seismic events. Consequently, a reliable seismic design approach for use in engineering practice...
Conference Paper
Full-text available
Urban growth has necessitated the construction of many large, deep basements in city centres. In many places, most notably London and South East England, these basements are founded upon stiff, over-consolidated clay strata. These clays exhibit long-term heave over many years after the construction of the basement structure, producing additional he...
Article
Structural or foundation rocking are effective ways to prevent the development of large force demands in building systems experiencing ground shaking. In practice, structural rocking may result in large displacements and therefore is often accompanied with dampers, while residual and differential settlements are sometimes a barrier for utilisation...
Conference Paper
Full-text available
A series of centrifuge experiments were performed with pile foundations in stratified soil to investigate the kinematic and inertial load effects during earthquakes. A single aluminium model pile was embedded into a soft kaolin clay overlying the dense sand. Each experiment was carried out in two flights, to study the kinematic and inertial load ef...