In this paper, an algorithm for calculation of active lateral pressure on retaining walls at seismic condition is presented. In this algorithm, that its formulation is based on lower bound of limit analysis method, by considering a stress discontinuity and finding the acceptable stress fields on its two sides, active force is calculated. Soil cohesion and internal fraction angle, also the cohesion and friction between the soil and wall are considered. Results are compared with other researchers and the algorithm validation is confirmed.

Pile group are vastly used in marine structures for several applications. Loadings exerted to these structures are divided into two main categories: lateral loading and vertical loading. All researchers agree to use vertical piles in the case of pure vertical loading where as the use of batter piles in the case of lateral loading is still in doubt. The behavior of batter piles in a pile group is somehow two-faced. Although batter piles reduce the lateral displacement of the pile group under lateral loading but they also cause stress concentration in batter pile and pile head. Thereby complete understanding of batter and vertical piles is of great importance. In our research, different pile group configurations are analyzed numerically that based on the finite difference method. Soil is modeled as a mohr-coulomb continuous medium obeying model and piles and pile head are assumed to be elastic concrete. To validate the simulation, results from numerical modeling are compared to those from available experimental data and analytical solution.

For analyzing and assessing the seismic vulnerability of masonry buildings, it is necessary to specify the main structural properties of walls such as stiffness, ultimate load bearing capacity, etc. Although micro modeling is essential in a brick wall, it is difficult and approximately impractical due to the pattern of arrangement of bricks and bed and head joints of mortar and their large quantity. In macro modeling, masonry materials are replaced with an equivalent homogeneous material. In the present research, a set of analytical equations was established for determining the mechanical properties of this equivalent homogeneous material. The results of the proposed method for homogenization of unreinforced brick walls were compared with those of detailed modeling in different situations of solid walls under in-plane loading, and it was found that this method provides suitable accuracy in estimation of the wall linear properties such as stiffness and the wall nonlinear properties such as ultimate strength. Additionally, this proposed modeling method is simple and quick and needs very little input data.

In this study, the effect of state parameter in elasto-plastic constitutive models on improvement of predicting sand behavior was studied, using DIANA-SWANDYNE II program. The centrifuge test results, which were obtained in VELACS workshop, were used in this study. The mechanical behaviors of centrifuge models under earthquake loading was predicted by using Pastor & Zienkiewicz Mark III constitutive model and the modified model and were compared with experimental results. The results show that the use of current state parameter can have a significant effect on improvement of predicting deformation, water pore pressure and acceleration caused by earthquake loading in soil structures.

Spatial data collection is a time/money consuming task in activities related to geospatial sciences. Spatial data integration increases the efficiency of spatial data through cost reduction. Therefore, developing matching algorithms is of vital importance in spatial data integration, data updating and data accuracy enhancement. The main objective of this research is to design and develop a semi-automatic vector matching system. The developed system simulates human brain process in its matching procedure. Priliminary results are promissing. Further reaseaches are required to examine the system efficiency.

Monitoring the behavior of earth dams during the stages of construction, impoundment and operation is of a great significance. The results obtained from monitoring can be used to check the validity of the design parameters and to improve the design of future dams. Maroon reservoir dam with the height of approximately 170m is one of the highest earth dams in Iran and is located in Khuzestan province in the southwest of Iran. In this dam, various types of instruments such as total pressure cells, piezometers, inclinometers and settlement plates have been installed within five sections to monitor the behavior of the dam. This dam had two phases of impoundments. In the first phase, the water level reached an elevation of 426m, but the reservoir was emptied due to some construction concerns. In the second phase of impoundment which was the main impoundment, the maximum water level reached an elevation of 485m.In this article, the results of three dimensional analyses of Maroon dam during the second impoundment using FLAC3D program are presented and are compared with the results obtained from the instrumentation data. This software involves finite difference method to carry out the computations. The reason for using three dimensional analyses was that the dam is constructed in a relatively narrow valley. Mohr-Coulomb constitutive model was used in the analyses in which the main input parameters consist of cohesion, angle of internal friction, bulk modulus and shear modulus of soil. The dam was modeled in 17 layers each with a thickness of 10m. Considering the actual time of construction, average rate of construction was calculated as 17cm per day. Therefore, for each layer of 10m thickness, 60 days was allocated for consolidation. It is concluded that a rather good consistency exists between the computational results and monitoring results. It is also shown that arching has taken place both along the dam axis and along the upstream-downstream direction; however, the magnitude of the arching has not been to an extent that could cause cracking or piping of the dam.

In construction of concrete floors, parts of the formwork are sometimes left in place as permanent structural elements. This is to achieve a more straightforward installation procedure and to minimize the future under deck form removal. The present research work deals with, an innovative floor system consisting of hollow-tiles and steel joists. In a hollow-tile floor system, gravity loads are transferred by the slab sitting on top of the blocks to the one way joist and then to the main beams. With the proposed new system the width of the hollow block is doubled so, it is relatively lighter than an ordinary hollow-tile floor system. The joists height is slightly bigger than that in an ordinary hollow-tile floor system; however, the hollow block height remains the same. Thin plastofoams sheets are placed on top of the blocks to fill the gap. During the construction, the fresh concrete weight is carried by temporary vertical posts. After removal of temporary posts, the service loads are transferred to the T beams. This paper provides details for the application of the proposed new floor system in a steel frame building under gravity and quasi static earthquake loading. Various spans and floor thicknesses have been examined and the details are presented.

In Iran, for Column Design, Double I shape Section is used due to lack of IPB profile. Double I shape column performance is ambiguous in existing steel structures, especially when subjected to seismic loading. In this paper, double I shape column behavior is evaluated with 3D nonlinear analyses. Monotonic behavior of 6 specimens and hysteretic behavior of other six specimens have been simulated. Half of specimens have been welded ordinarily simulating constructional habit of Iranian site welding and six other specimens have been welded ideally with complete manner. Finally behavior of two groups of specimens has been compared in the view of the following parameters such as bending and axial strength, stress concentration and collapse mechanism.

In this research, materially nonlinear dynamic analysis of concrete arch dam using Concrete Elasto-Plastic models is attempted. At first, common models for nonlinear analysis of massive plain concrete structures are investigated and finally concrete material model of Wiliam–Warnke (five parameters version) for tensional and compression failure is selected. This model is used versus other usual models such as Mohr-Coulomb and Drucker-Prager models for analysis of Morrow Point concrete arch dam under an intensive ground motion of order of 1.0g for the peak ground acceleration. A suitable algorithm for stress integration and conversion of engineering stresses to objective ones is proposed. This stress calculation is particularly desired in large deformations analysis. Fluid-structure interaction is also considered including water compressibility and reservoir bottom absorption. Staggered approach is used for coupled-fluid structure solutions. Although the foundation is considered as rigid. It is demonstrated that usual nonlinear plastic models such as Mohr-Columb and Drucker –Prager models unlike special concrete models are not capable to capture real behavior of such concrete structure. It is suggested that special concrete models such as William–Warnke must be used for the plastic nonlinear analysis of concrete arch dam.

During an earthquake, many stations record the ground motion, but only a few numbers of them could be corrected using conventional high-pass and low-pass filtering method and the others identified as highly contaminated by noise and as a result useless. There are two major problems associated to these noisy records. First, since signal to noise ratio (S/N) is low, it is not possible to discriminate between original signal and noise neither in frequency domain nor in time domain. The consequence is that it is not possible to cancel out the noise using conventional filtering methods. The second problem is about non-stationary characteristics of the noise. In other words, in many cases the characteristics of the noise are varying by time and in these situations, it is not possible to apply frequency domain correction schemes. For correction of acceleration signals contaminated with high-level non-stationary noise, there is an important question that is it possible to have estimation about the state of the noise in different bands of time and frequency? The wavelet multi-resolution analysis which decomposes a signal into different time-frequency components besides a suitable criterion for identification of the noise among each component provides the required mathematical tool for correction of highly noisy acceleration records. In this paper, the strong motion records of great earthquake events with Mw>5.5 in Iranian Plateau is corrected. For this purpose, first, signal to noise ratio is calculated for each record. If the value of this diagram is high enough, the signal is corrected with both methods and otherwise, the de-noising is applied using wavelet procedure. The effect of baseline correction of the final results is also investigated for each record. A comprehensive database containing the information of events, stations and correction parameters is also provided in this study.