International Journal of Civil Engineering
Volume:2 Issue: 2, Jun 2004

Air transportation effects on the process of country�s economic, social and cultural development, at macro and micro level, has obliged transport planners to estimate mathematical models for international air transport demand. International air travel in the recent decade has gained enormous importance, and this is due to increasing communication between various countries, especially in economic and tourism sectors. Therefore, as a result, annually, it�s share of total travel, has increased.The intention of this present research is to prepare a feasibility study of international air transport demand by using mathematical modeling, for Iranian airspace. After studying the background, macro models (simple time series models as exponential and multiplicational), were selected for air passenger modeling using a series of social and economical variables as indicators for air passenger potentials in the country and also variables for specifications related to Iran air transportation services. With respect to studying the background of the matter in Iran and other parts of the world, model estimation was performed by least square methods of regression. It ought to be mentioned that, model estimation was performed with respect to linear, multiplicational, exponential and logarithmic equations, using data from year 1982 to 1996. These results were calibrated & validated by using data of years 1997 to 2001.Finally using statistical tests, the final exponential model without dummy variables was established, to estimate international air passengers and it is believed as the best Iranian model.

The seismic response of pile-supported offshore structures is strongly affected by the nonlinear behavior of the supporting piles. Nonlinear response of piles is the most important source of potentially nonlinear dynamic response of offshore platforms due to earthquake excitations. It is often necessary to perform dynamic analysis of offshore platforms that accountsfor soil nonlinearity, discontinuity condition at pile soil interfaces, energy dissipation through soil radiation damping and structural non linear behaviors of piles.In this paper, an attempt is made to develop an inexpensive and practical procedure compatible with readily available structural analysis software for estimating the lateral response of flexible piles embedded in layered soil deposits subjected to seismic loading. In the proposed model a BNWF (Beam on Nonlinear Winkler Foundation) approach is used consisting of simple nonlinear springs, dash pots and contact elements. Gapping and caving-in conditions at the pile-soil interfaces are also considered using special interface elements. This model was incorporated into a Finite Element program (ANSYS), which was used to compute the response of laterally excited piles. A linear approach was used for seismic free field ground motion analysis. The computed responses compared well with the Centrifuge test results.This paper deals with the effects of free field ground motion analysis on seismic non linear behavior of embedded piles. Different parts of a BNWF (Beam on Nonlinear Winkler Foundation) model, together with quantitative and qualitative findings and conclusions for dynamic nonlinear response of offshore piles, are discussed and addressed in detail. The proposed BNWF model (only using the existing features of the available general finite element software) could easily be implemented in a more comprehensive model of nonlinear seismic response analysis of pile supported offshore platforms.

In this paper a structural damage detection algorithm using static test data is presented. Damage is considered as a reduction in the structural stiffness (Axial and/or Flexural) parameters. Change in the static displacement of a structure is characterized as a set of non-linear undetermined simultaneous equations that relates the changes in static response of the structure to the location and severity of damage. An optimality criterion is introduced to solve these equations by minimizing the difference between the load vector of damaged and undamaged structures. The overall formulation leads to a non-linear optimization problem with non-linear equality and linear inequality constraints. A method based on stored strain energy in elements is presented to select the loading location. Measurement locations are selected based on Fisher Information Matrix. Numerical and experimental results of a 2D frame represent good ability of this method in detecting damages in a given structure with presence of noise in measurements.

The purpose of the present study, is proposing a more flexible model comparing with linear regression model, to estimate the rate of household trip production and its prediction in the�project horizon. For this purpose, a combined model composed of poission distribution and the possible distribution of A. in the form of negative binominal distribution are used. Then the proposed model was conducted on a real case (Karaj City). Then the result of model processinghas been compared to. the real observation in the peak hours in Karaj city.

In this research, the Integrated Noise Model (INM), has been calibrated to perform the noise pollution evaluation in the vicinity of Mehrabad International Airport (MIA). First a conceptual model was developed to analyze the compatibility of airport noise with the land use based on the most widely accepted noise pollution standards. Second, the data generated from the INM package was compared with real data acquired from the test stations positioned around airport. Finally, the outputs of the calibrated model was compared with the noise pollution standards. The results show that more than 70 percent of the land use in the vicinity of airport are not compatible with the accepted noise levels. The generated noise contours was superimposed on the digital map of the city and the areas which violated the permitted levels was recognized. Moreover, the more noise sensitive facilities such as; hospitals, schools, and residential units can be positioned in areas which have the permitted noise levels. The model and the procedure can be used to design new airports. Noise evaluation of existing operational airports can be performed by the model developed in this research.

A numerical model is introduced for solution of shallow water flow equations with negligible physical dissipations due to canal roughness and turbulence effects. Two-dimensional velocity distribution and water depth of the flow field are computed by solving the depth average equations of continuity and motion. The equations are converted to discrete form using cell vertexfinite volume method on triangular unstructured mesh. The formulation of the added numericalviscosity is chosen in such a way that preserves the accuracy of numerical results. The accuracy ofthe model is assessed by computing the challenging case of inviscid frictionless flow in a canal with a 1800 bend. The computed results are compared with analytical solution which is obtainedfrom potential flow theory. Simulation of frictionless free surface flow in a constant width meandering sinusoidal canal is considered as an application of the model. The algorithm produced encouraging results.

Government agencies and the medical, insurance and automotive industries all have an interest in understanding the socio-economic costs of road crashes. These costs are estimated in most countries, and their computation methodology are continuously progressing as more refined costing methods, are used. This paper outlines two recent studies in Iran and Australia in order to compare crash cost estimation approaches. The analytical approaches and the results of similar studies in some other countries are also discussed It is shown that different approaches to estimating human costs and its components have considerable effects on the results. In both studies, the contribution to the total costs are human costs (50 to 60 percent), vehicle costs (30 percent) with the remaining 10 to 20 percent covering general costs.