Case Studies in Structural Engineering最新文献

Given the importance of pile foundations in geotechnical engineering for supporting high-significance structures such as bridges, high-rise buildings, power plant stations, offshore platforms and museums, it becomes a necessity to find the best pile foundation design in terms of performance and economy. The number of piles required might exceed several hundreds or even thousands while the pile foundation cost might exceed 20% of the construction cost of the superstructure. In this work the problem of finding optimized designs of pile foundations is examined and is performed in accordance to two design code recommendations, namely Eurocode 7 and DIN 4014. The proposed structural optimization procedure is implemented in two real-world cases both located in London, UK in order to assess the efficiency of the proposed design formulation.

Initial distortion and residual stress are well known as the most important initial imperfection factors and have a significant effect in decreasing the ultimate strength of compression members. The present work focuses on predicting the ultimate strength of welded box section steel compression members regarding initial imperfection factors. Beam compared with shell type of Finite Element (FE) models varied in slenderness ratio and initial distortion are used to assess the accuracy of present numerical results. The comparison of result between FE models and design strength formulations in some specifications are used to assess the ultimate strength formulations of bridge specifications according to the behavior of current steel compression members. It can be observed from numerical results that FE models and design strength by JSHB 2012 and AISC 2005/AASHTO 2010 have good agreement each other which means that the specifications have good capability in assessing the ultimate strength of steel compression members. Parametric study of the ultimate strain varied in slenderness ratio and load versus displacement curves of compression members are also introduced in order to perform more detail steel columns displacement behaviour. Finally, present work proposed a flowchart in designing steel compression members with the expectation that it will be helpful as reference for researchers and engineers in practical fields.

The exterior beam-column (EBC) joints in the second generation concrete structures (built prior to 1970s) were observed to underperform during earthquakes mainly due to the lack of shear reinforcement and improper construction practices. In this paper, results of a detailed parametric study conducted using 3D finite element analysis are presented to illustrate the performance of three types of substandard EBC joints that are typical to pre 1970s construction practices designed according to: (1) ACI 318-1971, (2) old Japanese practice and (3) old Indian practice. In addition, the influence of concrete strength, beam and column flexural reinforcements on the load carrying capacity of substandard EBC joints are investigated. The substandard joints analyzed in this study failed in a brittle fashion due to the shear failure of joint core concrete and anchorage slippage.

This paper presents test results of two connections tested under cyclic loading. The testing programme addressed connection with reduced beam section (RBS) versus without RBS moment connection. RBS connection is widely investigated and used in US, Japan and Europe. However, design of such type of connection is not presented and used in India. This study is conducted to learn, the advantages and usefulness of RBS connection against connection without RBS for Indian profiles. A theoretical model is also created with the finite element method and the results are compared with those obtained from the experimental study. The analysis observed that specimen without RBS performed poorly due to cracks started at the bottom flange weld. The specimen with RBS reached rotation capacity of 0.02 radians without damage in the welds.

This paper describes wind tunnel tests performed on wind tunnel models of the Talavera de la Reina cable stayed bridge. The work describes the aeroelastic model construction and it is focused on the evaluation and analysis of the mean and peak wind loads at the tower foundation and the cable anchorages since these data can be very useful by the bridge manufacturer as a support for the bridge design. The work is part of a complete wind tunnel study carried out to analyze the aeroelastic stability of the bridge.

The redevelopment of the Melbourne Park Tennis Centre incorporates something not previously seen at the home of a “Grand Slam” tournament – courts on the roof of a carpark building. To determine an appropriate structural design criterion for the suspended slabs, a study was undertaken on how vibrations induced by the players and external sources would be perceived. Following testing on existing courts and undertaking real time studies on forces exerted by tennis players, a series of criteria for acceptable vibrations in the structure was developed. The structure has now been successfully used during the 2013 and 2014 Australian Open tournaments.

In the present paper, a comprehensive finite element model of Karun III double curvature arch dam is calibrated based on the micro geodesies measurements and instrumentation. Thermal properties of concrete are obtained by transient thermal analysis and the results are compared with those obtained from thermometers. Thermal analysis features include air temperature, water layers temperatures, and the solar radiation on the exposed faces. Structural calibration features include thermal distribution within the dam body, dam self-weight, hydrostatic pressure, and silt load applied on the model of dam–reservoir–foundation system. Finite element model calibration provides updated information related to the current dam status and can be used for further safety evaluations.