2026-06-09T15:53:09+03:30 http://ijce.iust.ac.ir/browse.php?mag_id=30&slc_lang=en&sid=1

30-346 2026-06-09 10.1002

International Journal of Civil Engineering IJCE 1735-0522 2283-3874 2006 4 2 H. Oucief M.F. Habita B. Redjel In most cases, fiber reinforced self-compacting concrete (FRSCC) contains only one type of fiber. The use of two or more types of fibers in a suitable combination may potentially not only improve the overal properties of self-compacting concrete, but may also result in performance synergie. The combining of fibers, often called hybridization, is investigated in this paper for a cimentetious matrix. Control, single, two fibers hybrid composites were cast using different fiber type steel and polypropylene with different sizes. Flexural toughness tests were performed and results were extensively analysed to identify synergy, if any, associated with various fiber combinations. Based on various analysis schemes, the paper identifies fiber combinations that demonstrate maximum synergy in terms of flexural toughness. self-compacting concrete hybrid fibers toughness energy 2006 6 01 77 85 http://ijce.iust.ac.ir/article-1-346-en.pdf

30-347 2026-06-09 10.1002

International Journal of Civil Engineering IJCE 1735-0522 2283-3874 2006 4 2 H. Moharrami S.A. Alavinasab In this paper a general procedure for automated minimum weight design of twodimensional steel frames under seismic loading is proposed. The proposal comprises two parts: a) Formulation of automated design of frames under seismic loading and b) introduction of an optimization engine and the improvement made on it for the solution of optimal design. Seismic loading, that depends on dynamic characteristics of structure, is determined using "Equivalent static loading" scheme. The design automation is sought via formulation of the design problem in the form of a standard optimization problem in which the design requirements is treated as optimization constraints. The Optimality Criteria (OC) method has been modified/improved and used for solution of the optimization problem. The improvement in (OC) algorithm relates to simultaneous identification of active set of constraints and calculation of corresponding Lagrange multipliers. The modification has resulted in rapid convergence of the algorithm, which is promising for highly nonlinear optimal design problems. Two examples have been provided to show the procedure of automated design and optimization of seismic-resistant frames and the performance and capability of the proposed algorithm. optimization weight minimization earthquake resistant seismic resistant seismic analysis equivalent static loading Optimality Criteria steel frames sensitivity analysis 2006 6 01 86 105 http://ijce.iust.ac.ir/article-1-347-en.pdf

30-348 2026-06-09 10.1002

International Journal of Civil Engineering IJCE 1735-0522 2283-3874 2006 4 2 M.H. Baziar R. Ziaie_Moayed This paper highlights the effect of silt content on cone tip resistance in loose silty sand. In this study, twenty-seven cone penetration tests are performed in saturated silty sand samples with several different silt contents ranging from 10 to 50 percent. The samples are consolidated at three overburden stresses including 100, 200 and 300 kPa. It is shown that, as the silt content increases, the cone tip resistance decreases. In high percent of silt (30-50%), the cone tip resistance decreases more gently compared with low percent of silt (0-30%). It is also concluded that the method proposed by Olsen (1997) for stress normalization of cone tip resistance compared with the Robertson and Wride (1998) method has better agreement with the obtained results. To evaluate liquefaction potential of loose silty sand, the method presented by Robertson and Wride (1998) is also studied. The results showed that the use of Robertson and Wride (1998) method to estimate the fine content from CPT data causes some uncertainty especially for high silt content (FC>30%). Cone tip resistance Silty sand Stress normalization Liquefaction 2006 6 01 106 119 http://ijce.iust.ac.ir/article-1-348-en.pdf

30-349 2026-06-09 10.1002

International Journal of Civil Engineering IJCE 1735-0522 2283-3874 2006 4 2 S.A. Sadrnejad An important concern in rock mechanics is non-homogeneity as joints or fault. Adopting the joints as fractures, fractures are well known for their effects on the mechanical and transport properties of rock. It has been postulated that through fractured/jointed rock, mainly, the polygons turned to the shear vector (ti) are involved in the mobilization of shear resistance. Consequently, in order to locate the contact areas implicated into the shear-test it was firstly necessary to fix the shear direction. Moreover, since laboratory observations clearly show that only the steepest polygon surfaces touch the other sample, the identification of the potential sliding areas only requires the determination of the polygons which are faced to the shear direction and which, among them, are steep enough to be involved. The methodology to be discussed here is modeling of slip on the local and global levels due to the distribution of deformation procedure of the rock joint. Upon the presented methodology, more attention has been given to slip initiation and propagation through rock joint. In particular, softening in non-linear behaviour of joint in going from the peak to residual strengths imparts a behaviour often associated with progressive failure. A multi-plane based model is developed and used to compute plastic strain distribution and failure mechanism of rock joints. Validity of the presented model was examined by comparing numerical and test results showing the behavior of both homogeneous and jointed rock samples under general stress conditions. anisotropy jointed rock multi-axial stress state plasticity hardening/softening law. 2006 6 01 120 135 http://ijce.iust.ac.ir/article-1-349-en.pdf

30-350 2026-06-09 10.1002

International Journal of Civil Engineering IJCE 1735-0522 2283-3874 2006 4 2 B. Behnam M.H. Sebt H.M. Vosoughifar By identifying the damage index of a structure, in addition to a correct understanding from real behavior of the structure, the required criterion for strengthening would be given. Researchers have given many relations for determination of damage index but such relations have been based upon laboratory methods which challenge their usage in a broad term. In this paper two new methods are given for calculation of damage index. Surveying the first crack limit and total structure failure is based upon the formation of plastic joints in the first column and basic floor columns. To give a qualitative simple and functional damage index, the functional method was given in the form of a qualitative method with statistical analysis and collection of different views. Using this method is very simple and meantime offers suitable accuracy. With a numerical study on three models it was made clear that the difference of new method with amended method of Papadopolos in approximate 3%. This shows that given qualitative method is suitable to be used in a broad terms. Quality Damage Index Earthquake Urban Building Reformed Method 2006 6 01 136 145 http://ijce.iust.ac.ir/article-1-350-en.pdf

30-351 2026-06-09 10.1002

International Journal of Civil Engineering IJCE 1735-0522 2283-3874 2006 4 2 M. Naderi This paper introduces an innovative partially destructive method, called “Twist-off”, for the assessment of in situ concrete strength. In this method a 40mm diameter metal probe is bonded to a concrete surface by means of a high strength epoxy resin adhesive. To measure the concrete compressive strength, a torque is applied using an ordinary torque-meter and the maximum shear stress at failure is used to estimate the cube compressive strength by means of a calibration graph. The relationship between the results of this new method and compressive strengths of concrete cores is also presented in this paper. The average coefficient of variation of the results of this method was seen to be of the order of 8 percent and the correlation coefficients of its comparative results with concrete cube and core compressive strengths were found to be 0.97 and 0.90 respectively. In order to assess the performance of this method on site, tests were undertaken on a number of buildings. Although the method was found to perform well but with some of the structures tested, the differences between the strengths of sample cubes and estimated in situ compressive strength of concrete were seen to be significant. Concrete strength; In situ testing; Twist-off method 2006 6 01 146 155 http://ijce.iust.ac.ir/article-1-351-en.pdf