AMIRKABIR
Year:2003 | Volume:14 | Issue:56-B|Papers Count:6

Expert systems are receiving great attentions in construction industry to support decision making processes in diagnostics design repair and rehabilitation of the structures. Although several expert systems have been examined in engineering since the 1970s their applications in construction industry are rare. This was largely due to the lack of expert system tools available to represent the domain knowledge. Lack of flexibility applicability and robustness of the classical models have forced the scientists to discover the ability of the expert systems in problem solving of civil engineering. This paper presents an expert system for diagnosis the deterioration of concrete structures. This expert system emphasizes on cracking distress in reinforced concrete elements. A case study has been presented to examine and evaluate the proposed expert system. The system demonstrates a straightforward method for diagnosing the cause of reinforced concrete elements cracking

Fault movement during an earthquake may have severe effect on buried pipelines as a lifeline element. A few studies are carried out on the behavior of buried pipelines to this kind of damage and disruption. In most of these studies, the fault movements are modeled as two- dimensional. In this study, by modeling the pipe as a beam and the surrounding soil as nonlinear springs, the effect of three dimensional movement of fault on buried pipelines is investigated. Some important parameters such as; fault movement, depth of buried, geometrical characteristics of the pipe, angle of pipe- soil friction, angle of pipe- fault crossing, and the fault slip are considered in this study.

Colliding of adjacent buildings with each other during earthquake is one of the major seismic damages. Because of seism city of IRAN and the expansion of construction, it is necessary to consider a means to decrease or if possible, eliminate the pounding effect in buildings. This is feasible with studying of different factors, which affect pounding in the design stages of new structures or in the strengthening of old buildings. In this article, pounding effects has been studied and then experimental results regarding two models of moment resistance steel structures on shaking table with force vibration and seismic exciting is presented. Ultimately few methods for decreasing pounding effects such as increasing of interval between two structures, the use of an impact absorbing material and connecting the two structures to each other are considered. Test results show the importance of frequency content in pounding. It is also shown that connecting of two adjacent structures at the top level of short structure may be useful and the use of dissipating materials can reduce induced acceleration when pounding occurred! Results of this investigation can be used for steel structures strengthening, design and construction of new buildings.

Elasto-viscoplastic model is described first, and differential equation of visco-plastic strains is introduced with respect to time to use the model for the analysis of underground spaces include three linear and non-linear yield criteria: which is linear Mohr-Colomb, non-linear Hoek-Brown, and no-tension criteria. The corresponding relationships were derived for using in the computer program. The no-tension criterion is used for determination of the probable tension zones around the tunnel before Easto plastic analysis. A computer program was prepared in quick basic language capable of analyzing the ground around tunnels and underground spaces for linear and non-linear cases, and also to determine the stresses and strains in the tunnel surface in two-dimensional case. A horse-sheo shape tunnel was selected for analysis. One and two stage excavations, ground characteristics curve, pressure due to support system and the tension zones around the tunnel were analyzed and determined

Application of Cone Penetration Test, CPT have shown an increase in geotechnical design and site investigation due to measurement of soil characteristics, supplying continuous profile and incorporating a variety of sensors with it. Because of similarity between cone penetrometer and a model pile, research work has been concentrated in this field and therefore, there is a limited information for using CPT data in shallow foundation design. A static analytical model based on general shear failure mechanism of logarithm spiral has been developed for calculating directly bearing capacity of footings from q, by realizing foundation dimension, surcharge and data processing. Five current CPT direct methods for determining bearing capacity of footings have been investigated and criticized the proposed method and five others were compare to the measured capacity ranging from 1. 7 to 15 kg/cm2 of 32 footings with the width range from 0.3 to 3m compiled in a database. The statistical and cumulative probability approach for validation of predictive methods indicates favorable and optimistic results for proposed method and it can be considered in geotechnical practice.