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1 – 10 of over 3000Seyyed Pouya Alavinezhad and Hadi Shahir
The purpose of this study is to present a diagram for the lateral earth pressure of c–φ soils exerted on anchored walls in presence of surcharge.
Abstract
Purpose
The purpose of this study is to present a diagram for the lateral earth pressure of c–φ soils exerted on anchored walls in presence of surcharge.
Design/methodology/approach
To this end, two-dimensional plane strain modeling of anchored wall was carried out in Plaxis software. To validate the numerical model, two excavations with different specifications were simulated and the model results were compared with the available results. Subsequently, a parametric analysis was done and based on its results, a diagram was proposed for the lateral earth pressure of c–φ soils including the surcharge effects.
Findings
The proposed diagram without the surcharge and cohesion effects is a trapezoidal with zero value at the ground surface that is linearly approaching the apparent earth pressure of sand according to Terzaghi and Peck (1967) at 0.1H (H: wall height). The surcharge and cohesion effects at the ground level is 4 Ka*q and 0, respectively, and below 0.1H, they are treated as the same way for lateral earth pressure of a retaining wall. It should be emphasized that the apparent pressure diagram for design does not resemble the real distribution of earth pressure against the wall and it is for calculating the values of the anchors loads.
Originality/value
The available diagrams to determine the earth pressure exerted on the anchored walls are related to sandy or clayey soils and do not take the presence of surcharge into account. Thus, the proposed diagram is quite original and different from the previous ones.
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Hamed Arefizadeh and Hadi Shahir
Anchorage with concrete bearing pad is commonly used in Iran for stabilization of excavations because of the ease of construction, less costs and less time consumption than the…
Abstract
Purpose
Anchorage with concrete bearing pad is commonly used in Iran for stabilization of excavations because of the ease of construction, less costs and less time consumption than the soldier pile method. In this method, a wall facing which includes the concrete bearing pads at the location of the anchors and a shotcrete layer between the bearing pads is constructed parallel to the excavation operation similar to the nailing method.
Design/methodology/approach
In this paper, using the finite element software Abaqus, a three-dimensional model of the above-mentioned type of wall is constructed, and the effect of spacing and size of bearing pads on the wall behavior is discussed.
Findings
According to the obtained results, the size of the concrete bearing pads has little effect on wall deformations, but the internal forces and bending moments developed in the shotcrete layer between the bearing pads are greatly influenced by the bearing pads dimensions and spacing.
Originality/value
Owing to the discrete elements of the wall facing, the behavior of this system is completely three-dimensional.
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Iasef Md Rian, Dongkuk Chang, Jin-Ho Park and Hyung Uk Ahn
This paper presents a pop-up technique based on origamic architecture as a technological design solution for post-disaster temporary shelter systems. First of all, the concepts of…
Abstract
This paper presents a pop-up technique based on origamic architecture as a technological design solution for post-disaster temporary shelter systems. First of all, the concepts of disaster and post-disaster are briefly introduced, and the roles and needs of post-disaster temporary shelter systems, particularly in emergency periods, are reviewed. Second, pop-up techniques based on origamic architecture are briefly discussed. Third, a formal language for opening the cards of origamic architecture is introduced, out of which a geometric elasticity has been developed. With the language, a variety of flexible and expandable designs for shelter structures can be generated by incorporating different pop-up techniques. Finally, a prototype shelter has been constructed to demonstrate the adaptability and sustainability of the shelter within the local environment and the affected society, considering portability, low-cost, and easy in assembling by any unskilled person.
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P. Ryalls and A. Stevens
Outlines the methods used to construct two basements at the newBritish Library, and the precautions taken to monitor and prevent groundmovement and related damage to adjacent…
Abstract
Outlines the methods used to construct two basements at the new British Library, and the precautions taken to monitor and prevent ground movement and related damage to adjacent buildings and London Underground tunnels. Discusses the proposed construction sequence, the prediction of ground movements and the comprehensive survey and ground instrumentation programme installed. Explains the type, purpose and criteria for the instrumentation required and details their positioning in order to monitor possible damage, with particular reference to London Underground and St Pancras Station. Details the results of the survey over the nine‐year construction period, in comparison with predictions, and the plans for continuation of surveys until work is complete.
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Tamir Amari and Mohamed Nabil Houhou
This paper aims to investigate single pile and pile group responses due to deep braced excavation-induced soil movement in soft clay overlying dense sand. The analysis focuses…
Abstract
Purpose
This paper aims to investigate single pile and pile group responses due to deep braced excavation-induced soil movement in soft clay overlying dense sand. The analysis focuses first on the response of vertical single pile in terms of induced bending moment, lateral deflection, induced axial force, skin resistance distribution and pile settlement. To better understand the single pile behaviour, a parametric study was carried out. To provide further insights about the response of pile group system, different pile group configurations were considered.
Design/methodology/approach
Using the explicit finite element code PLAXIS 3 D, a full three-dimensional numerical analysis is carried out to investigate pile responses when performing an adjacent deep braced excavation. The numerical model was validated based on the results of a centrifuge test. The relevance of the 3 D model is also judged by comparison with the 2 D plane strain model using the PLAXIS 2 D code.
Findings
The results obtained allowed a thorough understanding of the pile response and the soil–pile–structure interactions phenomenon. The findings reveal that the deep excavation may cause appreciable bending moments, lateral deflections and axial forces in nearby piles. The parametric study showed that the pile responses are strongly influenced by the excavation depth, relative pile location, sand density, excavation support system and pile length. It also showed that the response of a pile within a group depends on its location in relation to the other piles of the pile group, its distance from the retaining wall and the number of piles in the group.
Originality/value
Unlike previous studies which investigated the problem in homogeneous geological context (sand or clay), in this paper, the pile response was thoroughly studied in a multi-layered soil using 3 D numerical simulation. To take into account the small-strain nonlinear behaviour of the soil, the Hardening soil model with small-strain stiffness was used in this analysis. For a preliminary design, this numerical study can serve as a practical basis for similar projects.
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The purpose of this paper is to describe cost effective structural design procedures to support catalytic reactors used in hydrocarbon industry. Three case studies are presented…
Abstract
Purpose
The purpose of this paper is to describe cost effective structural design procedures to support catalytic reactors used in hydrocarbon industry. Three case studies are presented using various reactor models. Modularization and transportation challenges are also discussed. The scope of the paper is limited only to the structural and construction aspects. The chemical and mechanical designs are not covered in this paper.
Design/methodology/approach
Finite element strategies are developed to model load transfer to reactor’s supports and to simulate soil/structure interaction. Fictitious nodes are generated at bolt locations to transfer the reactor’s loadings from the skirt to the pile cap. Soil-pile interaction is modeled using horizontal and vertical springs along the pile embedded length. Flexible supports are used at the bottom of the piles to stimulate the end bearing of the soil bed. The approach is demonstrated for several case studies of reactors support system.
Findings
The described algorithm is accurate and computationally efficient. Furthermore, the procedure can be used in practice for design catalytic reactor support.
Practical implications
The paper provides very useful guidelines that can be utilized in practice for design of catalytic reactor supports system. The procedure is cost effective and computationally efficient.
Originality/value
Extensive efforts were made in the past to develop economical procedures for catalytic reactors design. Much of the work focused on the process and mechanical aspects of catalytic reactors. Very limited work addressed the structural design aspects. Furthermore, no guidelines are available in current codes of practice.
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Udari Gunarathna, Chaminda Senarathna Bandara, Ranjith Dissanayake and Harsha Munasinghe
The lessons learned from the 2004 tsunami phenomenon fueled the government and other local authorities to strengthen the legitimate background to mitigate such devastation in…
Abstract
Purpose
The lessons learned from the 2004 tsunami phenomenon fueled the government and other local authorities to strengthen the legitimate background to mitigate such devastation in future events. This study aims to propose a standardized tsunami-resilient construction guideline for Sri Lanka by integrating existing local and international standards.
Design/methodology/approach
A comprehensive literature survey was carried out to undertake the study, with a wide-ranging content and thematic analysis of existing tsunami-resilient construction aspects in Sri Lanka. Integrating all existing guidelines with international standards, finally, a consolidated guideline with significant tsunami-resilient building aspects was proposed for stakeholders involved with the resilient built environment in tsunami-prone areas, particularly during the building construction in the coastal belt.
Findings
The existing tsunami-resilient guidelines in Sri Lanka follow similar aspects but in different dimensions. Compared to the international standards, few significant aspects create a gap in local guidelines. Thus, the findings demonstrated that the existing local guidelines must be modified and strengthened by mainstreaming into international practices.
Research limitations/implications
Existing guidelines are more concerned with structural aspects. Nevertheless, proper integration of local and international guidelines would be more favorable to minimizing existing local guidelines’ gaps. Further, a standardized tsunami-resilient building guideline would be a referring document for all stakeholders in tsunami-resilient constructions.
Practical implications
By aligning local guidelines with international standards, the reliability of the guidelines will be increased and direct the built environment to quality disaster-resilient constructions.
Social implications
Through a standardized guideline, the community can rely on tsunami-resilient construction in coastal cities.
Originality/value
The consolidated guideline further contains the essentials of city resilience in tsunamis and would be an excellent reference for relevant stakeholders than aligning with several guidelines.
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Aniruddha Uniyal and C. Prasad
Naitwar Bazar in the Upper Tons valley Indian Himalaya (Uttarkashi district of Uttaranchal in India) is showing signs of an impending disaster. This settlement has witnessed…
Abstract
Purpose
Naitwar Bazar in the Upper Tons valley Indian Himalaya (Uttarkashi district of Uttaranchal in India) is showing signs of an impending disaster. This settlement has witnessed active mass wastage during rainy season of 2003 which has caused damage to infrastructure (crucial road link), hospital (i.e. the sole health facility) and residential cum commercial area. The active mass wastage zone may take heavy toll of human lives during the rains. Therefore, the paper proposes examining this subject.
Design/methodology/approach
Field investigations were carried out to assess the damage during the past events, probe the causes of mass wasting hazard and to assess the elements at risk in order to evolve a disaster management strategy.
Findings
It is suggested that a series of prevention and mitigation measures (both structural and non‐structural) with the involvement of the local community are required to avoid the impending disaster in the area.
Originality/value
This paper highlights the need for hazard prognosis and vulnerability assessment in the remotest settlements of Himalayas in order to timely plan the awareness initiatives, response mechanism and structural and non structural mitigation measures. An attempt has also been made to bring forth importance of incorporating the disaster management component into the local developmental planning.
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A bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical…
Abstract
A bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view is given. The bibliography at the end of the paper contains 1,726 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1996‐1999.
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Sergio M. Alcocer and Víctor M. Castaño
The purpose of this paper is to provide an overview of structural design code development in Mexico, as an example of how code evolution has taken place in many countries, and to…
Abstract
Purpose
The purpose of this paper is to provide an overview of structural design code development in Mexico, as an example of how code evolution has taken place in many countries, and to discuss the challenges faced in improving code compliance and reducing vulnerability.
Design/methodology/approach
All building codes for Mexico City (1920‐2004) and current codes in Mexico were analyzed and compared in terms of their scope and contents. Emphasis is placed on understanding how design requirements, professional liabilities and overall performance requirements have evolved.
Findings
Structural codes have become more refined and complex, including at each revision the current state‐of‐the‐art knowledge. However, code compliance and code misinterpretation are prevalent, mainly because users are not familiar with the concepts and technologies involved. Also, it is stated that government authorities lack the technical capacity to identify code misinterpretations. Finally, it is stated that, for non‐engineered construction guidelines, other educational sources are needed in lieu of merely enforcing codes.
Research limitations/implications
Systematic research aimed at assessing the level of code compliance is needed.
Practical implications
A valuable source of changes and challenges in code implementation and compliance for students and practitioners is provided.
Originality/value
This paper summarizes information on the evolution of Mexican structural codes and offers a critique of the challenges and need for improving code implementation and reducing building vulnerability.
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