مجله پژوهش های زیرساخت های عمرانی
سال دوم شماره 1 (پیاپی 2، بهار و تابستان 1395)

Despite of the adequate performance of thin Steel Plate Shear Wall (SPSW) in last earthquakes and also during studies performed in the laboratories in all of the world, some problems and some defects such as lake of capability of commercial civil engineering software for modeling of the buckling and post buckling under lateral loading, lake of national Cod in this field of steel structures, have made an obstacle about its expanding in civil projects. Based on these mentioned problems, in this paper, a new and innovative model (method) is presented that the steel plate replaced with diagonal single brace member. This proposed method decrease analysis time due to decreased elements comparing with other presented methods. In other hand, the proposed method (model) provide a capability for static analysis and dynamic analysis of structures. Comparing the experimentally results with the proposed method shows a good convergence on stiffness and ultimate strength.

By examining the results of the analysis of the modification factor of the bridge with LRB isolators for x and y, respectively 2.32 and 3.95 and modification factor of bridge isolators ERB to x and y, respectively 2.57 and 4.25 was calculated. So modification factor of the bridge with LRB isolators for x and y is less than ERB isolators that represents the LRB bearings will cause that substructure is less inside nonlinear phase. Also the modification factor is less than the factor of “Publication 463” –it is in the x and y respectively 3 and 5- that indicates isolators reduce the nonlinear behavior of structural parts and lower general modification factor of the structure. The modification factor of isolators of bridge is less than the amount listed in the code. Although there is no significant difference but it less of it can be a reason for further investigation and as well as selected and proposed new factors for bridge with isolators in the codes.
In addition, the effect of reduction in the spans can be seen in two cases that there is no significant effect in various spans of bridge.

Long-term forecasting of maximum monthly precipitation (MMP) is very important for a variety purposes such as flood and runoff forecasting, irrigation scheduling and watershed management. In this study, the application of data mining technique (association rules) is offered to discover affiliation between MMP of Tabriz synoptic station and sea surface temperatures (SST) of the Black, Mediterranean and Red Seas considering the different lags. Data mining is a technology which helps extracting hidden predictive information from large data bases and thus it facilitates that decision makers to make proactive, knowledge-driven decisions. To examine the accuracy of the rules, support and confidence measures were calculated. The results show a relative correlation between the Mediterranean, Black and Red Sea SSTs and MMP of Tabriz synoptic station so that the confidence between the MMP values and the SST of seas is approximately 70 percent. Also the results indicate that the combination of the Mediterranean, Black and Red Sea SSTs to forecast the MMP of Tabriz synoptic station have a better performance.

Urmia Lake is one of the vital hydrological natural quarters of Iran which has met sever water level decrease. For this issue, checking the effect of local climate factors and changes in time series would be efficient solution for studying the behavior of water system in this area.In this research wavelet coherence measure is implemented for evaluating the relations and effect of hydrological processes over many years on Urmia water level fluctuations that is powerful method for testing proposed linkages between two time series. From continuous wavelet transform of two time series, wavelet coherence transform is determined which exposes the local correlation between two CWTs and it is very helpful to uncover the locally phase locked behavior. In this way, monthly Hydroclimatological data such as rainfall, runoff of Saeed Abad station and temperature, relative humidity and monthly evaporation of Lighvan station in West Azarbaijan were investigated.The results illustrate that runoff time series has the most effect on water level of Urmia Lake and the effect of temperature, relative humidity, evaporation and rainfall are in the next priorities to runoff.

Seepage of water from beneath of built structures on permeable soils causes uplift force along the contact of structure with foundation. This uplift force reduces hydraulic structure stability. Typically, these instabilities occur due to under-pressure development (uplift force), gradual inner degradation of foundation material (piping) or sand boil phenomenon. Thus, it seems necessary to calculate the pressure applied to the contact surface of the dam. One method for preventing piping phenomenon, reduction in exit gradient as well as decrease of uplift force beneath diversion dams includes implementation of weep hole. This study aims to study the effect of radius, depth and location of pipe drains under stilling basin upon how much uplift force decreases. The benefit of this study in agricultural field for soil and water engineers is to have a safe design of lined canals, weirs or diversion dams. To do this, numerical simulation of Tabriz diversion dam with Geo-Studio software was carried out. Results showed that application of drain pipe under the structure reduced uplift force respect to without drain under the structure. Increasing of drain radius; caused reduction of uplift pressure more but increased of seepage flow slightly. Installation of drain in upper part of stilling basin had a tendency to decrease uplift pressure more. Existence of drain near the stilling basin bottom caused in more reducing of uplift pressure than of installation of it in deeper depth.

It goes without saying that, dispersive soil might cause some geotechnical problems, although, in geo-environmental project, they could be used as an excellent contaminant absorbent due to their higher surface area and well exposed clay particles to soil pore fluid. Because of this environmental application, using disperse clay is common in many landfill projects. On the other hand, the dispersivity behavior of soils is known to be a function of clay mineral and concentration of salt in pore fluid. On this base, this paper gives some applicable graphs to estimate the concentration of salt needed to disperse clayey soils with the view of using in geo-environmental project based on the mineral types. The results indicate that, this system provides deep knowledge of salt concentration needed for disperse clayey minerals and mixture of minerals. It is shown that the effect of the clay microstructure is the important factor on the dispersivity behavior of clay minerals.