To improve the dynamic properties of soft soil, the cement treatment technique combined with fibre reinforcement can be employed In this study, the effects of two types of fibres (polypropylene and recycled carpet) on the hardening process and small-strain properties of cement-treated kaolinite and bentonite clays are investigated Cement-treated clay specimens were prepared using cement contents of 5%, 10% and 15% by weight of dry soil for the kaolinite samples, and 30%, 40% and 50% for the bentonite samples To investigate and understand the influence of different fibre types and contents, three different percentages of fibre content were adopted: 01%, 02% and 05% polypropylene fibres, and 05%, 075% and 1% carpet fibres The results of bender element tests on 126 cylindrical samples of cement-treated clay with various cement and fibre contents were analysed to discern the relationships between fibre and cement content and the small-strain mechanical properties, including the shear wave v

https://opus.lib.uts.edu.au/bitstream/10453/26700/4/2012006563OK.pdf

Small-strain properties of soft clay treated with fibre and cement

The present research intends to study the effects of the seismic soil-pile-structure interaction (SSPSI) on the dynamic response of buildings with various heights by conducting a series of shaking table tests on 5-, 10-story, and 15-story model structures. Two types of foundations for each case are investigated, including (1) a fixed-base structure, representing the situation excluding the soil-structure interaction; and (2) a structure supported by an end-bearing pile foundation in soft soil. An advanced laminar soil container has been designed that uses three-dimensional numerical modeling to minimize the boundary effects and to simulate free-field motion during the shaking table tests. Four real earthquake events, including Kobe 1995, Northridge 1994, El Centro 1940, and Hachinohe 1968, are imposed to each model. According to the experimental measurements, it is observed that the SSPSI amplifies the maximum lateral deflections and in turn interstory drifts of the structures supported by end-bea...

Physical Modeling of Seismic Soil-Pile-Structure Interaction for Buildings on Soft Soils

Influence of Size and Load-Bearing Mechanism of Piles on Seismic Performance of Buildings Considering Soil–Pile–Structure Interaction

Numerical optimization applying trust-region reflective least squares algorithm with constraints to optimize the non-linear creep parameters of soft soil

In this study, the accuracy of a fully nonlinear method against an equivalent linear method for dynamic analysis of soil-structure interaction is investigated comparing the predicted results of both numerical procedures. Three structural models, including 5-story, 10-story, and 15-story buildings, are simulated in conjunction with two soil types with shear-wave velocities less than 600 m/s. The aforementioned frames were analyzed under three different conditions: (1) fixed-base model performing conventional time history dynamic analysis under the influence of earthquake records, (2) flexible-base model (considering full soil-structure interaction) conducting equivalent linear dynamic analysis of soil-structure interaction under seismic loads, and (3) flexible-base model performing fully nonlinear dynamic analysis of soil-structure interaction under the influence of earthquake records. The results of these three cases in terms of average lateral story deflections and interstory drifts are determine...

Fully Nonlinear versus Equivalent Linear Computation Method for Seismic Analysis of Midrise Buildings on Soft Soils

The seismic excitation experienced by structures is a function of the earthquake source, travel path effects, local site effects, and soil-structure interaction (SSI) influences. The result...

/pdf/seismic-behavior-of-building-frames-considering-dynamic-soil-516066383n.pdf

Seismic Behavior of Building Frames Considering Dynamic Soil-Structure Interaction

In this study, an enhanced numerical soil-structure model has been developed which treats the behaviour of soil and structure with equal rigour. The proposed numerical soil-structure model has been verified and validated by performing experimental shaking table tests. To achieve this goal, a series of experimental shaking table tests were performed on the physical fixed based (structure directly fixed on top of the shaking table) and flexible base (considering soil and structure) models under the influence of four scaled earthquake acceleration records and the results were measured. Comparing the experimental results with the numerical analysis predictions, it is noted that the numerical predictions and laboratory measurements are in a good agreement. Thus, the proposed numerical soil-structure model is a valid and qualified method of simulation with sufficient accuracy which can be employed for further numerical soil-structure interaction investigation studies. Based on the predicted and observed values ...

/pdf/numerical-and-experimental-investigations-on-seismic-n1i5x9wbe5.pdf

Numerical and Experimental Investigations on Seismic Response of Building Frames under Influence of Soil-Structure Interaction

In this study, in order to evaluate adequacy of considering local site effect, excluding soil-structure interaction (SSI) effects in inelastic dynamic analysis and design of mid-rise moment resisting building frames, three structural models including 5, 10, and 15 storey buildings are simulated in conjunction with two soil types with the shear wave velocities less than 600 m/s, representing soil classes De and Ee according to the classification of AS1170.4-2007 (Earthquake actions in Australia) having 30 m bedrock depth. Structural sections of the selected frames were designed according to AS3600:2009 (Australian Standard for Concrete Structures) after undertaking inelastic dynamic analysis under the influence of four different earthquake ground motions. Then the above mentioned frames were analysed under three different boundary conditions: (i) fixed base under direct influence of earthquake records; (ii) fixed base considering local site effect modifying the earthquake record only; and (iii) flexible-base (considering full soil-structure interaction). The results of the analyses in terms of base shears and structural drifts for the above mentioned boundary conditions are compared and discussed. It is concluded that the conventional inelastic design procedure by only including the local site effect excluding SSI cannot adequately guarantee the structural safety for mid-rise moment resisting buildings higher than 5 storeys resting on soft soil deposits.

Soil-structure interaction vs Site effect for seismic design of tall buildings on soft soil

SUMMARY

In this study, to determine the elastic and inelastic structural responses of mid-rise building frames under the influence of soil–structure interaction, three types of mid-rise moment-resisting building frames, including 5-storey, 10-storey and 15-storey buildings are selected. In addition, three soil types with the shear wave velocities less than 600 m/s, representing soil classes Ce, De and Ee according to AS 1170.4–2007 (Earthquake action in Australia, Australian Standards), having three bedrock depths of 10 m, 20 m and 30 m are adopted. The structural sections are designed after conducting nonlinear time history analysis, on the basis of both elastic method and inelastic procedure considering elastic-perfectly plastic behaviour of structural elements. The frame sections are modelled and analysed, employing finite difference method adopting FLAC2D software under two different boundary conditions: (a) fixed base (no soil–structure interaction) and (b) considering soil–structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted, and the results in terms of the maximum lateral displacements and base shears for the above mentioned boundary conditions for both elastic and inelastic behaviours of the structural models are obtained, compared and discussed. With the results, a comprehensive empirical relationship is proposed to determine the lateral displacements of the mid-rise moment-resisting building frames under earthquake and the influence of soil–structure interaction. Copyright © 2012 John Wiley & Sons, Ltd.

S. Hamid Reza Tabatabaiefar

Papers

Seismic Behavior of Building Frames Considering Dynamic Soil-Structure Interaction

Fully Nonlinear versus Equivalent Linear Computation Method for Seismic Analysis of Midrise Buildings on Soft Soils

Numerical and Experimental Investigations on Seismic Response of Building Frames under Influence of Soil-Structure Interaction

Soil-structure interaction vs Site effect for seismic design of tall buildings on soft soil

An empirical relationship to determine lateral seismic response of mid-rise building frames under influence of soil–structure interaction