JOURNAL OF CIVIL ENGINEERING ISLAMIC AZAD UNIVERSITY
Year:2010 | Volume:3 | Issue:2|Papers Count:7

Significant damages in offshore areas and ports are induced by seismic liquefaction of saturated sand and silty sand. This paper gives a state of the art review of soil liquefaction evaluation procedures with special reference to seismic design guidelines for marine structures. Then, by introducing an important port of Iran, liquefaction evaluation has been performed in this site by implementing the mentioned procedures and complementary explanations have been presented. Finally, the results of liquefaction assessment have been compared with each other. Results of this study indicate that for a very important structure, there is an adequate consistency between different procedures in seismic guideline references.

Hydropower is one of the most renewable, non-radioactive and non-polluting sources of energy.Construction of Pumped Storage Hydropower Plants (PSHP) is one type of hydropower developments. The first stage in development and design of PSHP is finding the optimum location. Site selection of PSHP has effected by several criteria. In the current study we use the application of methods developed in the decision sciences: Spatial multiple criteria decision making (SMCDM) using weighted linear combination (WLC) and Ordered Weighted Average (OWA) with the help of geospatial data analysis in a Geographic Information System (GIS) environment instead of conventional method.In this method, there are uncertainties in criteria weight, risk adverse/risk taking of decision maker, normalize function of criteria maps. These uncertainties are investigated using PSHP site selection model based on multi-criteria decision-making system (MCDM) and GIS. Results show suitability maps are not affected by criteria weights and normalize function. SMCDM model (WLC or OWA) and risk adverse of decision maker influence on the site selection suitability maps.

Endurance Time (ET) method is an dynamic push-over analysis. In this method, structures are subjected to specially designed intensifying acceleration functions and their response is monitored during the analysis time. The excitation in each time of this analysis is introducer of specific earthquake hazard level. This method, tries to estimate the response of structures in earthquakes with different intensity and return periods, with considerable less analysis effort.With respect to multidirectional nature of earthquake and necessity of bi-directional analysis of some structures, in this paper, a method is introduced for bi-directional seismic analysis with ET method. For represent and evaluation of this method a moment frame structures is subjected to bi-directional ET analysis.Proficiency and precision of the results is showed by comparing with the results of time history nonlinear analysis with 7 pair of ground motions in two direction and 4 hazard levels (totally 28 NTH analyses).

It has been found that Mass Damper can reduce the maximum displacements of these structures effectively. However in many cases, it is important to reduce both displacement and acceleration simultaneously. In this paper, seismic control of one, four and eight story buildings with various torsional properties are studied when different dampers at different locations are used. The reduction in maximum edge displacement and accelerations are assumed as response parameters. The results indicate that tuned mass damper is effective in simultaneous control of acceleration and displacement and its effectiveness increases with increase in height of structure. For torsionally stiff buildings, the most effective cases are installing damper at both stiff and flexible edges.

Each dam can breach for various reasons and its flood may result in considerable damage. For this reason, estimating the effective parameters on dam-breach flood wave attenuation and this flood routing are very important. In this study, the effect of side slope of cross section is studied on dam-breach flood wave attenuation. This study uses a model of flood wave propagation based on Saint-Venant equation and an analytical model of wave propagation in rectangular channels, to provide a comprehensive model for dam breach flood wave attenuation in trapezoidal and triangular channels also. Results of this study are leading to find the dynamic wave model in these cross sections. Also it is determined that discharge attenuation factor is a function of channel characteristics such as side slope of cross section, in addition to Froude number, dimensionless wave period and dimensionless wave number that were achieved in last researches. At final, results of model compared with real observations of a dam failure and results of a numerical model.

Construction delays became an integral part of the project’s construction. Since a contractor is under a strict duty to complete on time, Delay to contractors’ progress is one of the major sources of claims and disputes in the construction industry. Most construction contracts contain express provisions under which the period allowed for the contractor to undertake and complete the works can be extended. These provisions cater for delays that are neither the fault nor the responsibility of the contractor. Such provisions obviously benefit the contractor, who will not be liable to pay damages for delay during the period for which time is validly extended. Generally, within an extension of time clause, the contractor will be obligated to submit notices and detailed particulars within a specified time frame. The general purpose of this paper is to discuss and compare conditions of contracts provisions for extending of time in Iran and international standards (JCT, ICE and FIDIC). In particular, the paper focuses on shortcomings of Iranian General Conditions of Contracts regarding to provisions of extending of time.

Highway alignment optimization based on cost minimization requires comprehensive formulation of costs sensitive to alignment and development of efficient solution algorithms. In order to solve real world problems the optimization algorithms should work directly with a Geographic Information System (GIS) which stores relevant geographic information, such as land boundaries, environmentally sensitive regions, and topographic data.This thesis offers a method for extract and correcting necessary information from existing maps in National Cartographic Center and making a GIS environment for highway alignment optimization procedure.In the mentioned GIS environment the study area, is divided into several non-regular zones. A new algorithm is offered for solving the highway alignment optimization problem in GIS environment with non-regular zones.