Civil Engineering Infrastructures Journal
Volume:49 Issue: 2, Dec 2016

Exceeded losses of nonstructural components from structural ones in most demolished buildings in previous earthquakes and its limitation on functionality of critical facilities and building serviceability after earthquakes should be got the point of view for accounting loss of building as a merit for building performance. This paper attempts to demonstrate the significant role of distribution pattern of building nonstructural components in height accounting for economic losses due to seismic excitation. To achieve this purpose a new modified distribution of nonstructural components in height is proposed for three typical steel moment frame models by office occupancy and comparative assessments between two competing distribution of nonstructural components are conducted. Dealing with discussions, it could be concluded that the economic losses could be reduced by more astutely situating building nonstructural components in height considering type of dominated demands in a specific story without requirement to any alternation in component's type or quantity.

This paper investigated the effects of combining fibers with self-consolidating concrete (SCC). 12 series of test specimens were prepared using three kinds of fibers including steel, polyphenylene sulfide (PPS) and glass fibers with four different volumes fractions and one specimen without fibers as a reference sample.
All plans were subjected to fresh concrete tests. For mechanical behavior of concrete, compressive, tensile and flexural strength, toughness, fracture energy and force-displacement curves has been studied. Fresh (rheological) properties were assessed using L-Box, Slump flow and T-50 tests. results show that concrete workability is reduced by increasing fiber volume fraction; among different fibers the PPS fibers have less negative effects on rheology. On the contrary, these fibers can improve the splitting tensile, flexural strength, toughness and fracture energy of SCC significantly; however strength of compressive is decreased by increasing the amount of fibers. Adding steel fibers to SCC increases energy absorption eminently.

In this research, a 2D laterally averaged model of hydrodynamics and water quality, CE-QUAL-W2, was applied to simulate water quality parameters in the Ilam reservoir. The water quality of Ilam reservoir was obtained between mesotrophic and eutrophic based on the measured data including chlorophyll a, total phosphorus and subsurface oxygen saturation. The CE-QUAL-W2 model was calibrated and verified by using the data of the year 2009 and 2010, respectively. Nutrients, chlorophyll a and dissolved oxygen were the water quality constituents simulated by the CE-QUAL-W2 model. The comparison of the simulated water surface elevation with the measurement records indicated that the flow was fully balanced in the numerical model. There was a good agreement between the simulated and measured results of the hydrodynamics and water quality constituents in the calibration and verification periods. Some scenarios have been made base on decreasing in water quantity and nutrient inputs of reservoir inflows. The results have shown that the water quality improvements of the Ilam reservoir will not be achieved by reducing a portion of the reservoir inflow. The retention time of water in reservoir would be changed by decreasing of inflows and it made of the negative effects on the chlorophyll-a concentration by reduction of nutrient inputs and keeping constant of discharge inflow to reservoir, the concentration of total phosphorus would be significantly changed and also the concentration of chlorophyll-a was constant approximately. Thus, the effects of control in nutrient inputs are much more than control in discharge inflows in the Ilam reservoir.

This paper describes the effects of reinforcement by randomly distributed nylon fibers and addition of nanoclay on some engineering properties of a typical asphalt concrete. The properties of asphalt concrete reinforced by different percentages of 25 mm nylon fibers have been compared with those of the mixtures containing different percentages of nanoclay and those in which both the fibers and nanoclay have been included. Engineering properties, including Marshall stability, resilient modulus, dynamic creep and fatigue life have been studied. Nylon fibers have been used in different percentages of 0.1, 0.2, 0.3 and 0.4% (by the weight of total mixture), and nanoclay has been used in 2, 4 and 7% (by the weight of bitumen). It is found that the addition of fibers is more effective than the nanoclay for increasing the resistance against fatigue cracking. However, nanoclay improves the resistance of the mixture against permanent deformation better than the nylon fibers. The results also show that the mixture reinforced by 0.4% of nylon fibers and containing 7% of nanoclay has the highest resilient modulus, Marshall stability and fatigue life. However, the mixture containing only 7% of nanoclay has the highest resistance against permanent deformation.

This paper aims at investigating the influence of partial replacement of Portland cement with ultrafine fillers compared to limestone powder on the durability and mechanical characteristics of concrete. For this purpose, ultrafine calcium carbonate materials with different specific surface areas of 9.7 and 15.1 m2/g and limestone powder (0.72 m2/g) were used. The results indicate that the ultrafine fillers enhanced the durability properties compared to the mixtures containing limestone. For instance, ultrafine fillers provided up to 20% higher concrete surface resistivity and 20% lower rapid chloride migration test (RCMT) coefficient, while limestone mixes showed equal or even lower durability levels compared to the plain mixture with 0% supplementary cementitious materials. The influence of filler materials on the compressive strength was not significant. However, regardless of the surface area, incorporating filler materials at levels up to 5% led to somewhat higher compressive strengths compared to the plain mixture. Generally, it seems that using finer fillers may lead to more durable concrete mixes.

The problem of propagation of plane wave including body and surface waves propagating in a transversely isotropic half-space with a depth-wise axis of material symmetry is investigated in details. Using the advantage of representation of displacement fields in terms of two complete scalar potential functions, the coupled equations of motion are uncoupled and reduced to two independent equations for potential functions. In this paper, the secular equations for determination of body and surface wave velocities are derived in terms of both elasticity coefficients and the direction of propagation. In particular, the longitudinal, transverse and Rayleigh wave velocities are determined in explicit forms. It is also shown that in transversely isotropic materials, a Rayleigh wave may propagate in different manner from that of isotropic materials. Some numerical results for synthetic transversely isotropic materials are also illustrated to show the behavior of wave motion due to anisotropic nature of the problem.

Nonlinear static procedure (NSP) is a common technique to predict seismic demands on various building structures by subjecting a monotonically increasing horizontal loading (pushover) to the structure. Therefore, the pushover analysis is an important part of each NSP. Accordingly, the current paper aims at investigating the efficiencyof various algorithms of lateral load patterns applied to the structure in NSPs. In recent years, fundamental advances have been made in the NSPs to enhance the response of NSPs toward nonlinear time history analysis (NTHA). Among the NSPs, the philosophy of “adaptive procedures” has been focused by many researchers. In the case of utilizing adaptive procedures, the use of incremental force vector considering the effects of higher modes of vibration and stiffness deteriorationsis possible and seems that it can lead to a good prediction of seismic response of structures. In this study, a new adaptive procedure called energy-based adaptive pushover analysis (EAPA) is implemented based on the work done by modal forces in each level of the structure during the analysis and is examined for steel moment resisting frames (SMRFs). EAPA is inspired by force-based adaptive pushover (FAP) and story shear-based adaptive pushover (SSAP). FAP has applied modal forces directly into load patterns; SSAP, on the other hand, has implemented the energy method in system`s capacity curve for measuring the equivalent movement. EAPA has enforced the concept of energy directly in load pattern; so that by using the modal forces-movements an energy-based adaptive algorithm is obtained. Hence, the effects of higher modes, deterioration in stiffness and strength, and characteristics of a specific site are incorporated and reflected in applied forces on the structure. Results obtained from the method proposed a desirable accordance with the extracted results from NTHA over the height of the structure.

Large water distribution systems can be highly vulnerable to penetration of contaminant factors caused by different means including deliberate contamination injections. As contaminants quickly spread into a water distribution network, rapid characterization of the pollution source has a high measure of importance for early warning assessment and disaster management. In this paper, a methodology based on Probabilistic Support Vector Machines (PSVMs) is proposed for identifying the contamination source location in drinking water distribution systems. To obtain the required data for training the PSVMs, several computer simulations have been performed over multiple combinations of possible contamination source locations and initial mass injections for a conservative solute. Then the trained probabilistic SVMs have been effectively utilized to identify the upstream zones that are more likely to have the positive detection results. In addition, the results of this method were compared and contrasted with Bayesian Networks (BNs) and Probabilistic Neural Networks (PNNs). The efficiency and versatility of the proposed methodology were examined using the available data and information from water distribution network of the City of Arak in the western part of Iran.

Nowadays, as a result of increased terrorist and bomb attacks throughout the globe in the vicinity of strategic buildings, designing these structures against impact loads, particularly the blast-related ones, has been taken into more consideration. The current procedure for designing the structure against an explosion is a design against the local failure of the current elements in the first step and then, in the next step, against local damage as well as tactful thinking to prevent this damage from spreading to other parts of the structure. The present research investigates the impacts of explosives, derived from probable terror–stricken scenarios inside and outside a strategic four-story steel building with a special moment frame system. Then, the resistive capacity of the damaged building (due to blast) has been evaluated against the progressive collapse, and finally, the rate of the collapse risk and the reliability of the structure have been obtained by presenting a probable method. Thus, the vulnerable parts inside and outside the building are identified and safety measures have been determined, so that in case of no safety or excessive collapse risk- access to dangerous parts of the building could be reinforced or limited. Results show that progressive collapse probability and reliability of the building are 57% and 43% respectively.

Water is the most essential component for sustaining lives of humans and other living creatures. Supplying potable water with adequate residual pressure is a fundamental responsibility of city administration, which they do during normal conditions. But sometimes, abnormal conditions are formed resulting pressure deficient conditions during the daily operations of water distribution networks. These are caused due to common occurrences such as pump failure, pipe bursts, and isolation of major pipes from the system for planned maintenance work and excessive firefighting demands. Total water stop conditions may arise, when the major source supplying water to the city fails in natural disaster such as floods, Tsunami, earthquake or manmade disaster such as terrorist attack. Unlike the pipe failure, longer time is required for restoring water in case of source failure condition. In such situations, the quantity of water is generally decreased and the water distribution systems (WDS) may not be able to satisfy all consumers’ demands. In this context, the assumption that all demands are fully satisfied regardless of the pressure in the system becomes unreasonable. A realistic behavior of the network performance can only be attained by considering demands to be pressure dependent. This paper aims to describe how pressure dependent demand analysis is useful for the simulation of disaster scenario due to source failure of the Shirpur town. The simulation of failure scenario is carried out using WaterGEMs software. The paper also aims to prepare the action plans for the recovery of water supply in such crisis conditions.

In this article the general non-symmetric parametric form of the incremental secant stiffness matrix for nonlinear analysis of solids have been investigated to present a semi analytical sensitivity analysis approach for geometric nonlinear shape optimization. To approach this aim the analytical formulas of secant stiffness matrix are presented. The models were validated and used to perform investigating different parameters affecting the shape optimization. Numerical examples utilized for this investigating sensitivity analysis with detailed discussions presented.

Dam spillways are the structures that lead rightly and safely the outflow downstream, so that the dam integrity can be guaranteed. Many accidents with dams have been caused by an inadequate spillway design or insufficient capacity. To accurately respond the hydraulic spillways, designers use physical modeling for designing this kind of structures. The scale effect in the spillway modeling, as a result, leads to the difference between the measured data and the prototype. In this study, an experimental model of Germi-Chay Mianeh dam spillway was made in three 1:100, 1:75, and 1:50 scales. Then, the water level in upstream of the spillway crest was measured in seven discharges and compared to 1:50 scale (basic scale), the percentage of water level difference on the crest was calculated in two physical models with 1:100 and 1:75 scales. Results revealed that as the scales of ogee spillway with an arc in plan and converging training walls decrease using Froude simulation, the effect of viscosity and surface tension increase in turn resulting in decreasing discharge coefficient. In this study, the scale effect in discharge coefficient ogee spillway was stated with K' equation. Using model family approved that the minimum Reynolds and Weber numbers which are 3.1×104 and 270, respectively indicated the minimum scale effect and thus, it is possible to avoid the effect of viscosity and surface tension in ogee spillway with an arc in plan and with converging training walls. Moreover, results obtained from the small scale which has been simulated using Froude simulation could be extrapolated to the prototype.