ASIAN JOURNAL OF CIVIL ENGINEERING (BUILDING AND HOUSING)
Year:2005 | Volume:6 | Issue:1-2|Papers Count:8

On December 26th, 2003 a devastating earthquake occurred in the southeastern Iran, causing a large number of collapsed buildings and human casualties. This study addresses the earthquake damage to buildings and its human casualties. Firstly, we analyze overall tendency of damage on basis of damage statistics comparing preceding surveys on building vulnerability and the relation between human casualties and building damage, and also on the basis of a questionnaire survey conducted in the stricken area. Finally, seismic response of an adobe masonry structure is analyzed by using Discrete Element Method, which can demonstrate the simulation of collapse of the structure.      

The strut-and-tie method can be used for the design of regions of structures where the basic assumptions of flexure theory, namely plane sections remaining plane before and after bending, are not applicable. Such regions occur near force discontinuities arising from concentrated forces or reactions and near geometric discontinuities such as abrupt changes in cross section etc. The strut-and-tie method of design is based on the assumption that appropriate regions in concrete structures can be analysed and designed using hypothetical pin-jointed trusses consisting of struts and ties connected at nodes. Although IS 456:2000 recommends the strut-and-tie method for design of corbels, no guidelines are given for determination of concrete strut and node dimensions and for the allowable stresses for design. The ACI Code 318-02 on the other hand, gives explicit and practical recommendations related to the design of structural members using the strut-and-tie method. To amplify the application of these recommendations to the design of structural concrete a complete example on the analysis and design of a double corbel using the strut-and-tie method has been presented.    

This paper explores the use of artificial neural networks in predicting the failure load of castellated beams. 47 experimental data collected from the literature cover the simply supported beams with various modes of failure, under the action of either central single load, uniformly distributed load or two-point loads acting symmetrically with respect to the center line of the span. The data are arranged in a format such that 8 input parameters cover the geometrical and loading properties of castellated beams and the corresponding output is the ultimate failure load. A back-propagation artificial neural network is developed using Neuro-shell predictor software, and used to predict the ultimate load capacity of castellated beams. The main benefit in using neural network approach is that the network is built directly from the experimental or theoretical data using the self-organizing capabilities of the neural network. Results are compared with available methods in the literature such the Blodgett's Method and the BS Code. It is found that the average ratio of actual to predict failure loads of castellated was 0.99 for neural network, 2.2 for Blodgett's Method and 1.33 for BS Code. It is clear that neural network provides an efficient alternative method in predicting the failure load of castellated beams.      

Dramatic development of digital computation allows for the probabilistic assessment of structural integrity and the derivation of the design values for the relevant variables to meet a predefined level of performance when inherent variability is accounted for. In this paper, a probability-based method useful for economic proportioning of the dimensions of a structural element with uncertain material and geometrical properties under uncertain action is developed and demonstrated for a glued laminated thin-webbed timber beam composed of glulam flanges and plywood web. The proposed method enables a comparative analysis of the effective material utilization in the construction of glued thin-webbed timber beams.      

Super heavy high-strength concretes with destiny 3800-4200 kg/m3 for protection against radiation are developed. Increased concrete density is obtained by complex use of wastes products of heavy silicate-lead glasses (brand DF) production as dispersed cement filler, disperse superlasticizer (SP) carrier, fine and coarse fillers.      

Probabilistic design methods are very attractive as they allow a systematic treatment of uncertainties and to set performance requirements in terms of explicit safety targets. The design of thin-webbed timber beams involves appreciable structural analysis of the load effect because of the various stress levels to be checked at different points of a cross-section. The presence of uncertainties in the response or the structural capacity of such beams may significantly alter the conjectured performance. This paper considers varying degrees of variability (measured by the coefficients of variation) in some selected design variables to derive appropriate safe design values for all relevant design variables at predefined performance levels for a typical cross-section of an I-beam. The design point concept of the First-Order Reliability Method (FORM) is employed to facilitate the needed solution. Design tables for typical cross-sections composed of glulam flanges and different species of plywood for the web are provided.      

The assessment of seismic performance of buildings under future earthquakes is becoming an important problem in earthquake engineering. Some important buildings are considerably old and therefore their strengths and ductilities are less than strength and ductility demands. Such buildings must be strengthened to resist future earthquakes. First the structural model is developed and then based on seismic hazard and seismic risk analysis or code quantities, the design (or control) parameters are determined. The next step consists of defining the damage indices. Then the nonlinear dynamic analysis is carried out. Finally based on numerical results one can determine the amount and how of strengthening. In this paper some damage indices are reviewed and then a formulation is presented for considering the importance of columns and lower stories failure. As an example, a ten story building in Tehran is analyzed.      

Dwellings in rural areas of the developing countries do not have artificial systems of cooling or heating. These buildings, especially in hot-dry climate, are provided with natural cooling systems. Parameters which influence natural cooling of such buildings can be classified as (i) surrounding environmental factors and (ii) parameters associated with the buildings. Present paper describes influence of above parameters in providing natural cooling of residential buildings in general and in hot-dry climate in particular. These effects are supported by case studies of few residential buildings.