scholarly journals Numerical evaluation of seismic response of shallow foundation on loose silt and silty sand

2014 ◽  
Vol 123 (2) ◽  
pp. 365-379 ◽  
Author(s):  
ALI ASGARI ◽  
ALIAKBAR GOLSHANI ◽  
MOHSEN BAGHERI
Keyword(s):  
Seismic Response ◽  
Numerical Evaluation ◽  
Shallow Foundation ◽  
Silty Sand

Experimental and numerical evaluation of innovated T-resisting frames with haunched horizontal plate girders

2020 ◽  
Vol 23 (8) ◽  
pp. 1669-1682
Author(s):  
Payam Ashtari ◽  
Mohammad Rahnemoun ◽  
Irandokht Rasouli
Keyword(s):  
Seismic Response ◽  
Numerical Evaluation ◽  
Horizontal Plate ◽  
Link Length ◽  
Main Concept ◽  
Shear Yielding ◽  
Plate Girders ◽  
Modeling Techniques ◽  
Test Result ◽  
Abaqus Software

In this article, a novel configuration for innovated T-resisting frames is proposed. New configuration uses haunched beams with three configurations as horizontal plate girders with prismatic link beam. Using haunched beams confirms T-resisting frame main concept with shear yielding which results in better seismic performance. Haunch configuration leads to achieve any link length ratio especially for very short links. To evaluate seismic response of the haunched beam, a half scale T-resisting frame specimen with haunched configuration at side column face is subjected to a proper cyclic loading protocol. In addition, the same frame is modeled in ABAQUS software to validate the modeling techniques. Results of verification showed good conformity between numerical analysis and test result. Finally, several numerical examples are studied to investigate the effect of height and span length on T-resisting frames with different haunch locations and various link lengths in seismic response. It was found that shear yielding of haunched beams results in high ductility and more energy dissipation and a proper behavior in comparison with prismatic ones.

Influence of Foundation Type on Seismic Performance of Buildings Considering Soil–Structure Interaction

2016 ◽  
Vol 16 (08) ◽  
pp. 1550043 ◽  
Author(s):  
Aslan S. Hokmabadi ◽  
Behzad Fatahi
Keyword(s):  
Seismic Response ◽  
Pile Foundation ◽  
Soil Structure ◽  
Soft Soil ◽  
Shallow Foundation ◽  
Shaking Table ◽  
Soil Structure Interaction ◽  
Structure Interaction ◽  
Raft Foundation ◽  
Different Types

In selecting the type of foundation best suited for mid-rise buildings in high risk seismic zones, design engineers may consider that a shallow foundation, a pile foundation, or a pile-raft foundation can best carry the static and dynamic loads. However, different types of foundations behave differently during earthquakes, depending on the soil–structure interaction (SSI) where the properties of the in situ soil and type of foundation change the dynamic characteristics (natural frequency and damping) of the soil–foundation–structure system. In order to investigate the different characteristics of SSI and its influence on the seismic response of building frames, a 3D numerical model of a 15-storey full-scale (prototype) structure was simulated with four different types of foundations: (i) A fixed-based structure that excludes the SSI, (ii) a structure supported by a shallow foundation, (iii) a structure supported by a pile-raft foundation in soft soil and (iv) a structure supported by a floating (frictional) pile foundation in soft soil. Finite difference analyzes with FLAC3D were then conducted using real earthquake records that incorporated material (soil and superstructure) and geometric (uplifting, gapping and [Formula: see text] effects) nonlinearities. The 3D numerical modeling procedure had previously been verified against experimental shaking table tests conducted by the authors. The results are then presented and compared in terms of soil amplification, shear force distribution and rocking of the superstructure, including its lateral deformation and drift. The results showed that the type of foundation is a major contributor to the seismic response of buildings with SSI and should therefore be given careful consideration in order to ensure a safe and cost effective design.

scholarly journals Geophysical and Geotechnical Site Characterization at Lagos Central Area of Lagos State, Nigeria

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Rafiu Adegbola ◽  
Kayode Oyedele ◽  
Elizabeth Abidoye
Keyword(s):  
Central Area ◽  
Maximum Load ◽  
Shallow Foundation ◽  
Silty Sand ◽  
Cone Penetration ◽  
Engineering Structures ◽  
Shallow Subsurface ◽  
Subsurface Geology ◽  
Electrical Sounding ◽  
A Site

Introduction: Geophysical characterization refers to the collection of information associated with subsurface features. Geotechnical involves engineering structural performance studies which are used to obtain information on the physical properties of soil and rock around a site to design earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions. Aim: The study was aimed at characterizing the subsurface formations for the purpose of determining its capacity to withstand engineering structures. Materials and Methods: Geophysical techniques involving eight (8) vertical electrical sounding (VES) and Wenner array were carried out with two (2) traverses. Geotechnical investigation involving cone penetration test (CPT) was also carried out. Results: The results obtained were presented as 1D resistivity profiles and Pseudo-sections of 2-D. Three (3) geo-electric layers were delineated within the study area and these comprise of topsoil, peat or clay and silty sand. The CPT results were used in the calculation of bearing capacity using Bustamante and Gianeselli equation for pile foundations and Meyehorf equation to determine the maximum load the materials can withstand respectively. Conclusion: The shallow subsurface geology was adjudged to be mechanically unstable with low penetration resistance values up to the depth of 11m. The methods conformed and confirmed that shallow foundation was considered unsuitable for the intended engineering structure. Keywords: Meyehorf, Bustamante and Gianeselli, Subsurface, Geology, Unstable, Foundation.

REASONING ON IMPLEMENTATION OF FROST PROTECTED SHALLOW FOUNDATIONS

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Lilita Ozola ◽  
Guntis Andersons
Keyword(s):  
Data Processing ◽  
Design Method ◽  
Temperature Data ◽  
Shallow Foundations ◽  
Shallow Foundation ◽  
Silty Sand ◽  
Design Parameters ◽  
Climatic Data ◽  
Foundation Design ◽  
The Baltic

Implementation of frost protected shallow foundations (with insulation) in frost susceptible soils in the areas of the Baltic region is an item under discussion. A design method recommended by EN ISO 13793 has been applied. The design base is the EN 1997-1 which includes conditions and valid climatic data for the localities in the Republic of Latvia. The study contains the results of external air temperature data processing from the last 70 years, and consequently a determination of a freezing index value, and moreover pointing out the variation depending on the reference period taken. Results of temperature data processing for decades of winter seasons testify that quite distinctive frost protection levels may be defined for shallow foundation design parameters depending on the number of frost seasons sampled. The specific design results were obtained for eccentrically loaded columnar spread foundations of an unheated building insulated to reduce heat loss from the soil below the foundations keeping the subgrade soil unfrozen. As a result of the research the conclusion about the benefits expected has been presented, based on the comparison of concrete consumption and soil excavation volumes from different localities in Latvia. It has been concluded that the cost effectiveness of heated foundations correlates closely with the type of frost-heaving soil. Use of frost protected shallow foundations in clayey soils leads to an increase of ground volume to be excavated and filled back, and concrete consumption for foundations decreases. In silty sand soils, if the required foundation depth is less than some definite level, both reductions may be achieved by shifting the ground, and in concrete consumption as well.

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