2024-03-28T23:37:19Z
https://ijstc.shirazu.ac.ir/?_action=export&rf=summon&issue=392
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
STRENGTHENING OF RC BEAMS IN FLEXURE USING FERROCEMENT
Assessment of the effectiveness of ferrocement strengthening techniques i.e., cast insitu Ferro-mesh layers and precast ferrocement Laminate is the aim of this experimentalinvestigation. To accomplish this objective, ten (10) reinforced concrete beams including onecontrol beam have been intentionally designed and detailed to fail in flexure. Prior tostrengthening, beams have been tested under two-point loading till service limit. Beams have beenstrengthened in the flexural dominant region only and tested to failure under the same loadingarrangement. It has been concluded that strengthening through cast in situ Ferro-mesh layer is themost efficient technique, whereas strengthening of the beams by using precast FerrocementLaminate B is not only easy to implement at household level, but is also promising in terms ofenhancing load carrying capacity, stiffness and ductility.
ferrocement
ferro-mesh
laminate
layers
flexural strengthening
2013
12
18
353
365
https://ijstc.shirazu.ac.ir/article_1792_dd18c74c2283430cad3e8a11e9455788.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
EXPERIMENTAL AND NUMERICAL ASSESSMENT OF FRP STIRRUPS
DISTANCE ON CYCLIC BEHAVIOR OF RC JOINTS
Many reinforced concrete structures are exposed to corrosive environment which canlead to damage of the reinforcing steels. These members include coastal structures subjected towind-born salt spray and seawater, as well as bridges beams and decks subjected to deicing salt.Design engineers should prevent the deterioration of reinforcing steel, especially transversestirrups. Using FRP materials in new concrete members has attracted researchers’ interests due toFRP high resistance against corrosion. Distance of FRP stirrups plays a key role in the cyclicbehavior of joints and energy absorption magnitude. In this study, experimental and finite elementinvestigations have been studied to assess the effects of stirrup distances on the cyclic behavior ofconcrete joints. In the experimental study, two half-scale concrete joints with the same beam andcolumn dimensions and longitudinal steel reinforcing characteristics but different distance oftransverse FRP stirrups were tested under cyclic loading. Besides presenting and analyzing themain results and photographs of the experimental tests, the made ANSYS finite element modelswere compared and validated with these tests. Moreover, the distances of FRP stirrups were variedin finite element models. According to experimental and finite element method results, the jointswith congested stirrups had not only higher ductility and energy dissipation, but also hadadditional capacity, as much as 12% relative to the non-ductile joint with wider distance stirrups.
Concrete joint
FRP stirrup
Finite element method
ductility
cyclic behavior
experimental results
2013
12
18
367
381
https://ijstc.shirazu.ac.ir/article_1793_31aeb83a71f0c5ef4081205968710fab.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
PRODUCTION OF ENDURANCE TIME EXCITATION FUNCTIONS:
THE CMA EVOLUTION STRATEGY APPROACH
Endurance Time (ET) method is a recently developed response-history based analysisprocedure for seismic assessment and structural design in which structures are subjected to apredesigned intensifying excitation function, and their performance is evaluated based on theirresponse at different excitation levels. Generating efficient excitation functions, which is essentialfor functionality of the method, leads to a complex large-scale optimization problem. In this paper,the Covariance Matrix Adaptation Evolution Strategy (CMA-ES), which has found manyapplications in solving continuous optimization problems, is employed to produce the excitationfunctions. The results reveal the good performance of the algorithm in generating ET excitationfunctions (ETEF) with reasonable accuracy and time efficiency.
Endurance time method
seismic response history analysis
intensifying excitation function
the
covariance matrix adaptation evolution strategy
2013
12
18
383
394
https://ijstc.shirazu.ac.ir/article_1794_c125bf04ca2a7b7b9ad24fca1e9cc031.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
SEISMIC BEHAVIOR OF STEEL MOMENT RESISTING FRAMES
ASSOCIATED WITH RC SHEAR WALLS
In this paper, the influence of increasing the height of building on the seismic behaviorof dual structural systems in the form of steel moment resisting frames accompanied withreinforced concrete shear walls has been investigated. Common structures experience inelasticstage of behavior encountering the seismic loads and the applied energy will be dissipated. Thenonlinear responses of the structural models have been evaluated in this research. As a result, someparameters such as ductility factor of structure (μ), over-strength factor (Rs) and responsemodification factor (R) for the mentioned structures have been studied. To achieve theseobjectives, the buildings have 10 and 20 stories and contain such structural systems used toperform the pushover analyses having different load patterns. Regarding the results, it seems thatthe response modification factor (R) for the mentioned structural system is assumed to be higherthan the value which is used in Iranian Code of Practice for Seismic Resistant Design of Buildings[Standard No.2800]. Analytical results showed that the ductility factor and the responsemodification factor increased as the structure height increased. In contrast, the over-strengthfactors increased by decreasing the height of the structure.
Dual system
steel moment resisting frame
shear wall
steel bracing
Reinforced concrete
seismic
behavior
2013
12
18
395
407
https://ijstc.shirazu.ac.ir/article_1795_02013bd292c60867ed490ceb3e5bed7b.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
TEACHING-LEARNING-BASED OPTIMIZATION ALGORITHM FOR SHAPE
AND SIZE OPTIMIZATION OF TRUSS STRUCTURES WITH
DYNAMIC FREQUENCY CONSTRAINTS
The complicated problem of truss shape and size optimization with multiple frequencyconstraints is investigated in this paper. A recently developed metaheuristics called teachinglearning-based optimization (TLBO) algorithm is used for the first time to solve this kind ofproblem. Contrary to other metaheuristics, the procedure of TLBO is simple to implement since notuning parameters need to be adjusted. Analyses of structures are performed by a finite elementcode in MATLAB which is used in conjunction with an optimization code based on TLBO.Various benchmark problems are solved with this technique and the results are compared withthose found by other methods including metaheuristics such as PSO, HS and FA. In all test cases,the results show that TLBO leads to very satisfactory results i.e. lighter structures which satisfy allfrequency constraints. The results of this study indicate excellent inherent capacity of the approachin dealing with complicated dynamic non-linear optimization problems.
truss structures
non-linear dynamic optimization
frequency constraints
teaching-learning-based
optimization (TLBO)
2013
12
18
409
421
https://ijstc.shirazu.ac.ir/article_1796_806e02f7ddc42566f462aecc90d40e5c.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
DETERMINATION OF ULTIMATE LOAD CAPACITY OF
CONICAL AND PYRAMIDAL SHELL FOUNDATIONS
USING DIMENSIONAL ANALYSIS
Surveys of the literature indicate that shell foundations are economical structuralelements which can be considered as the alternatives of flat foundations. However, the advantageof shell elements in geotechnical engineering has not been explored yet, and these foundations arestill being treated as flat footings. The objective of this study is to investigate the geotechnicalbehavior of two types of shell foundations under axial loading and present a comprehensiveformulation for bearing capacity of such foundations. For this purpose, a series of laboratory testswere carried out on six types of shell foundations, namely conical and pyramidal shell foundations.Different shell foundation geometries and Buckingham-Pi theorem were employed to formulatethe ultimate load capacity. Experimental results from previous investigations on shell footingswere used to verify the proposed formulations. Results of the present laboratory tests haveindicated that the pyramidal shell foundations show higher bearing capacities compared to theircorresponding conical ones and as the thickness of foundation increases, bearing capacitydecreases. Also, load bearing capacity equations of shell foundations determined from dimensionalanalysis have shown a reasonably good agreement with experimental results.
Shell foundation
Buckingham-Pi theorem
non-dimensional parameter
laboratory test
ultimate load
capacity
experimental investigation
2013
12
18
423
435
https://ijstc.shirazu.ac.ir/article_1797_28704770cdc0e45619ed97e6d9d0b795.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
REVEALING THE CHAOTIC NATURE OF RIVER FLOW
Chaotic analysis has been performed on the river flow time series before and afterapplying the wavelet based de-noising techniques in order to investigate the noise content effectson chaotic nature of flow series. In this study, 38 years of monthly runoff data of three gaugingstations were used. Gauging stations were located in Ghar-e-Aghaj river basin, Fars province, Iran.Noise level of time series was estimated with the aid of Gaussian kernel algorithm. This step wasfound to be crucial in preventing removal of the vital data such as memory, correlation and trendfrom the time series in addition to the noise during de-noising process. A comprehensive chaoticassessment was conducted to study the relationship between the wavelet noise reduction processesand the changes in the chaotic behavior of the river flow time series. To investigate the time serieschaotic behavior, some of the most common non-linear criteria are utilized which are distinguishedas the chaos indicators. The changes in the signal’s average power, the Lyapunov exponents, thecorrelation dimension and the reconstructed phase space were estimated. Studying the averagesignals power analysis’ results presents the evident impression of de-noising procedure on the riverflow time series. The variations of the Lyapunov exponents of time series as a consequence ofpreprocessing indicated a significant influence of the wavelet based de-noising on revealing thetime series chaotic behavior. Results depicted that the lesser noise components result in loweringthe largest Lyapunov exponents. Besides, fractal dimension and correlation dimension of the denoisedseries were almost the same while they were totally different before de-noising. This alsoconfirmed the commonly claimed sensitivity of correlation dimension to the existence of noise.The correlation dimension results depicted an obvious difference between the signal’s chaoticbehavior before and after the do-noising procedure. Changes in the reconstructed phase spaceswere also noticeable after de-noising process by wavelet techniques. Results confirm theimportance of de-noising before any chaotic assessment. Also, results show that a chaoticphenomenon such as river flow may depict completely random behavior due to the noise contentwithin it. Therefore, in order to better explore inherent chaotic behavior of natural time series, suchpre-processing can accompany common chaotic assessment procedures.
Chaotic behavior
Wavelet
noise reduction
river flow
2013
12
18
437
456
https://ijstc.shirazu.ac.ir/article_1798_617a4cd050247ee0f9910b948d70ef26.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
EXPERIMENTAL EVALUATION OF THE H/V SPECTRAL RATIO
CAPABILITIES IN ESTIMATING THE SUBSURFACE
LAYER CHARACTERISTICS
Microtremor data have been carried out for microzonation studies and disastermitigation in urban areas. Over a period of two decades, the Nakamura’s H/V spectral ratiomethod was recognized as a simple and cost effective method in seismological geotechnics. Inorder to identify the soil layers characteristics, microtremor measurements were performed in 6different regions in Iran. These sites are located in different parts of the south, center and east ofIran. Regarding the study, 471 recorded microtremors on an area about 700 km2 were processed.In addition, the results of 227 refraction tests, 386 electrical resistivity tests and 197 boreholeswere evaluated. Based on the analysis results, the resonance frequency of each station wasestimated from the peak of the H/V spectral ratio components. Conducting the boreholes orgeophysical investigations enabled the thickness of the sedimentary cover to be determined.Different places were selected as study areas namely, Bam, Bushehr, Qeshm Island, Mashhad,South Pars, and Qom. In order to develop the sedimentary thickness, an attempt has been made toderive a formula to correlate the frequency of the horizontal-to-vertical, (H/V) spectral ratio peaks(f0) to the sedimentary cover thickness (h). The obtained equations in the different sites indicatethat the relationship between these two parameters has a power form and it is significantly affectedby the subsurface topography and material properties. It is also observed that both shape of basinand sedimentary thickness have a significant influence on the relation formula parameters.
Microtremor
H/V spectral ratio
microzonation
site effect
2013
12
18
457
468
https://ijstc.shirazu.ac.ir/article_1799_557518dd0989cf379fa352568fddc988.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
DEVELOPING RFID-BASED ELECTRONIC SPECIMEN AND TEST CODING
SYSTEM IN CONSTRUCTION QUALITY MANAGEMENT
Although the collection of a detailed, accurate and sufficient volume of information,and subsequent timely delivery are vital for effective quality control and management inconstruction, existing methods for material and specimen tests and laboratory activities aremanually reliant on the human recourse to paper and pencil. Data collected using manual methodsare time and labour-intensive. They are also error-prone due to the reluctance of workers tomonitor and record the flow of large quantities of tests. This study investigates an automatedapproach that deals with a Radio Frequency Identification (RFID) facilitated quality managementsystem. The proposed system focuses on the gathering, monitoring, managing, and sharing ofaccurate data amongst all participants (i.e. consultants, contractors and owners) and also in thematerial test laboratory. In this research, the need for a new coding system is highlighted in whichRFID tagging has to be taken into consideration. In order to automate the task of specimenidentification and quality data collection in any laboratory activity, each RFID tag is equipped witha unique Electronic Specimen and Test Code (ESTCode). An ESTCode is used as a specimen andtest identity code, which forms the base of reports and contains related information for a particularspecimen and test. In order to form the backbone of technology adoption in real scenarios, and toidentify driving factors in this field, this paper also introduces an implementation framework forthe selected technology in construction quality management.
Automated data collection
construction projects
electronic code
quality management
RFID
2013
12
18
469
478
https://ijstc.shirazu.ac.ir/article_1800_debe2abe7ad50cd51e114cd53110f1fc.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
CAR COMMUTERS' MODE CHANGE IN RESPONSE TO TDM
MEASURES: EXPERIMENTAL DESIGN APPROACH
CONSIDERING TWO-WAY INTERACTIONS
Many studies have shown that individuals’ responses to urban traffic congestion, asusually assumed by policymakers, are significantly different from their respected actual behavior.This paper adopts a behavioral approach to examine this difference, using the design of experimentprinciples and binary logit models. In this approach, five transportation demand management(TDM) measures including three push and two pull measures were investigated. Then, effects andcontributions of the measures in diverting car commuters to seven existing non-car modes weretaken into account. This study uses the stated preferences of 288 individuals who regularly usetheir private cars to access their job locations in the central Tehran area, to calibrate seven non-carmode models. The results show that when considering each mode separately, pull measures arenecessary to regulate the market share of each non-car mode. Analysis of the effects of themeasures in considering non-car modes shows that although their contributions are about 14% fortransit accessed by walking and 7% for taxi, they have never contributed more than 5% to othermodes.
Transportation demand management measure
stated preference
binary logit model
design of
experiments
mode change
2013
12
18
479
490
https://ijstc.shirazu.ac.ir/article_1801_024c2f00b468924a99a86d37053af46d.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
EMPSACO: AN IMPROVED HYBRID OPTIMIZATION ALGORITHM
BASED ON PARTICLE SWARM, ANT COLONY AND
ELITIST MUTATION ALGORITHMS
This research presents an efficient and reliable swarm intelligence-based approach, antcolony optimization and elitist-mutated particle swarm optimization. Methods of particle swarmoptimization (PSO) and ant colony optimization (ACO) and elitist mutation particle swarmoptimization (EMPSO) are co-operative, population-based global search swarm intelligencemetaheuristics. PSO is inspired by social behavior of bird flocking or fish schooling, while ACOimitates foraging behavior of real life ants and Elitist mutation taken from genetic mutation fromgenetic algorithm techniques. In this study, we explore a simple approach to improve theperformance of the PSO method for optimization of multimodal continuous functions. Theproposed EMPSACO algorithm is tested on several test functions from the usual literature andcompared with PSO, PSACO and GA (Genetic Algorithm). Results showed that the effectivenessand efficiency of the proposed EMPSACO method had suitable accuracy to optimize multimodalfunctions.
Particle swarm optimization
ant colony
elitist mutation
metaheuristics
EMPSACO
2013
12
18
491
501
https://ijstc.shirazu.ac.ir/article_1802_e8a7cb2955e24b18bafc13f54bbd0587.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
A COMPARATIVE STUDY ON EXECUTIVE INDICATORS
IN CIVIL PROJECTS OF SU AND SUMS
The purpose of this study is to identify the way of dealing with the components ofproject implementation in civil projects of Shiraz University (SU) and Shiraz University ofMedical Sciences (SUMS), to compare the executive indicators in civil projects of bothuniversities. Indeed, results of studies on executive indicators of civil projects at SU and SUMShave been presented as articles at the Second International Conference on Construction and ProjectManagement ICCPM 2011 in Singapore; and the International Conference on Civil Engineeringand Transportation ICCET 2011 in Ji Nan, China, respectively. This study, however, focuses onthe comparison between the executive indicators of the civil projects at both universities; based onthe ideas of the decision-makers and authorities of the projects. In this study it has been found thatthe difference between some indicators is small. It means that the ideas of both groups in bothuniversities are similar or close to each other; which may show the accuracy in completing thequestionnaire and the methodology used. In this paper, the results of this comparative study arepresented and discussed.
Project management
executive indexes
managers
experts
consultants
contractors
2013
12
18
503
511
https://ijstc.shirazu.ac.ir/article_1803_8e88e652a352521052d69483c76aa186.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2013
37
C+
EFFECT OF HIGH RANGE WATER REDUCERS (HRWR) ON THE PROPERTIES
AND STRENGTH DEVELOPMENT CHARACTERISTICS OF
FRESH AND HARDENED CONCRETE
Research is underway to increase the strength of concrete with the addition of chemicaland mineral admixtures. The use of High Range Water Reducers (HRWR) has been increasedmany times in the last two decades. In this research the effect of two types of commerciallyavailable HRWR (Superplasticizers) are studied on the properties of concrete in fresh andhardened state. The strength development characteristics of concrete have been studied with theaddition of the HRWR. The research has shown the selection of appropriate HRWR for the desiredresults of concrete in fresh and hardened state is a critical decision for the performance of theWRWR.
Concrete
high range water reducers
mineral admixtures
2013
12
18
513
517
https://ijstc.shirazu.ac.ir/article_1804_76d4661c73662b13db0d2d4181edfe5d.pdf