Print ISSN: 1992-7428

Online ISSN: 2706-686X

Volume 5, Issue 10

Volume 5, Issue 10, Summer and Autumn 2008, Page 1-132


Mechanical Properties of Porcelinite Reinforced Concrete Beams

Ayad A. Slaby; Khalil I. Aziz; Ali Farhan Hadeed

Iraqi Journal of Civil Engineering, 2008, Volume 5, Issue 10, Pages 1-24
DOI: 10.37650/ijce.2008.39407

The researches in Iraq has expanded in the field of material technology involving
the properties of the light weight concrete using natural aggregate aviable in westran of Iraq.
Researches work on porcelinite concrete has been carried out in several Iraqi Universities.
The study is deals with mechanical properties of porcelinite aggregate concrete by casting
(273) different specimens. These properties are, compressive strength, flexurale strength,
splitting strength, static modulus of elasticity and absorption. The results indicated that the
structural light weight aggregate concrete produced from local porcelinite aggregate is
suitable to used as a structural concrete, it can produce structural light weight concrete of
compressive strength varies from (23.0 to 29.8) MPa with the density ranges from (1745 to
1855) kg/m3, by using cement content about (550 and 650) kg/m3.Such concrete exhibited
good mechanical properties. It gave the values of splitting tensile strength, modulus of
rupture and modulus of elasticity, 75%, 90% and 60% from those of normal weight concrete
respectively owning the same compressive strength and meeting the requirement of ACI-213

DEVELOPMENT OF RISKMANAGEMENT SYSTEM IN  CONSTRUCTION PROJECTS USING SIMULATION

Iraqi Journal of Civil Engineering, 2008, Volume 5, Issue 10, Pages 1-40
DOI: 10.37650/ijce.2008.45129

ی
 
 
 
 
 
 
This research aims to highlight the role of risks management in presenting a formalapproach to entry decisions to the markets of construction through the adoption of theanalytical hierarchy techniques, and simulation, as a technique in selecting particularrisk responses.To attain the aim of the research, special data which deal with the topic of risksmanagement, and their techniques, were collected from personal interviews ofspecialists of designers and executives of construction projects.The results of data analysis of samples have shown that risks of fluctuation of supplyand demand on materials, equipment or labor and changes in government policy are the most emerged risks with respect to qualitative assessment and the most highlight risksof relative importance are risks of changes in government policy and the fluctuation ofsupply and demand on materials and internal factors. And risk responses which arerepresented by contingency and specifying a clause in the contract which is concernedwith the changeable circumstances have gained the largest share of importance ascompared with other alternatives.In the light of what have been reached by the surrounded risks of the constructionproject, a management system has been constructed which can be adopted in qualitativeassessment of risks and in simulating this assessment ,so that can be depended on inquantitative assessment of risks through quantifying the influence of risks on projectcost by using simulation technique. To gain from the advantages of computer, acomputer program has been designed that depends on the bases of the managementsystems which have been suggested to be constructed.

SHEAR STRENGTH OF PORCELINITE AGGREGATE REINFORED CONCRETE BEAMS

Ali Farhan Hadeed; Kahlil I. Aziz; Ayad A. Slaby

Iraqi Journal of Civil Engineering, 2008, Volume 5, Issue 10, Pages 25-46
DOI: 10.37650/ijce.2008.45120

Research in Iraq has expanded in the field of material technology involving the
properties of the light-weight concrete using natural aggregate. Research work
on porcelinite concrete has been carried out in several Iraqi Universities.
However , despite the great practical importance of such concrete in
construction fields ,very limited amount of work has been carried out to
investigate the (shear strength) of structural light-weight aggregate concrete ,
therefore it is important to study the properties and their structural behavior. In this work an attempt is made to study shear strength of porcelinite reinforced
concrete beams without (stirrups). The results have been compared with the
results predicted by the equations of International codes, such as ACI 318M-02,
BS-8110 codes and with some authors' equations as for, Hanson. The
experimental results also have been compared with results obtained from normal
weight concrete specimens that had been prepared for this purpose. The study
mainly deals with the structural behavior of porcelinite reinforced concrete
beams without stirrups, especially the shear strength, besides, the short-term
deflection, strain and cracks. The variables are, compressive strength ranging
between (23.0-29.8) MPa and reinforcement percentages ranging between
(0.0174-0.0307). A total of 12 beams are tested; (9) are light weight concrete
beams without stirrups and (3) are normal weight concrete beams, also without
stirrups. The dimensions of all those beams are 135 * 260 * 1800 mm. The
structural results more often, give values 2.9 times more than that of (ACI-02)

Modeling of Polymer Modified-Concrete Strength with Artificial Neural Networks

Abdulkader I. Abdulwahab Al-Hadithi; Khalid R. Mahmood Al-Janabi

Iraqi Journal of Civil Engineering, 2008, Volume 5, Issue 10, Pages 47-68
DOI: 10.37650/ijce.2008.14123

ABSTRACT: In this paper, artificial neural networks (ANNs) are used in attempt to obtain the strength of polymer-modified concrete (PMC). A database of 36 case records is used to develop and verify the ANN models. Four parameters are considered to have the most significant impact on the magnitude of (PMC) strength and are thus used as the model inputs. These include the Polymer/cement ratio, sand/cement ratio, gravel/cement ratio, and water/ cement ratio. The model output is the strength of (PMC). Multi-layer perceptron trained using the back-propagation algorithm is used. In this work, the feasibility of ANN technique for modeling the concrete strength is investigated. A number of issues in relation to ANN construction such as the effect of ANN geometry and internal parameters on the performance of ANN models are investigated. Design charts for prediction of polymer modified concrete strength are generated based on ANN model. It was found that ANNs have the ability to predict the strength of polymer modified concrete, with a very good degree of accuracy. The ANN models developed to study the impact of the internal network parameters on model performance indicate that ANN performance is reality insensitive to the number of hidden layer nodes, momentum terms or transfer functions. On the other hand, the impact of the learning rate on model predictions is more pronounced.keywords:; Artificial Neural networks; Strength; Polymer Modified Concrete; Modeling.

CHEMICAL AND PHYSICAL PROPERTIES OF SOME TYPES OF CEMENT AVAILABLE IN LOCAL MARKET

Mahmoud Kh. Mohammed

Iraqi Journal of Civil Engineering, 2008, Volume 5, Issue 10, Pages 69-89
DOI: 10.37650/ijce.2008.14121

AbstractThere is no doubt that the type and properties of cement extremely affect the general properties of produced concrete .Cement is one of the main ingredients of cement past phase in concrete. In present study chemical and physical properties of four types of Portland cement available in Iraqi local market were studied ,these types as follow : two types of ordinary Portland cement Kubaisa (Iraqi cement) and Ismnta (Jordanian cement) and the others of sulfate resisting cement Torab alsabia (Lebanese cement ) and Al-qaim (Iraqi cement).Chemical analysis of the four types of cement were conducted in Baghdad central laboratory in National Center for Constructional Laboratories and Researches (NCCLR) and Al-qaim factory laboratory .The physical tests were conducted in the concrete laboratory of Al_anbar university-college of engineering including standard cement paste ,initial and final setting and compressive strength of cement mortars.The results indicate that the local cement (Kubaisa and Al-qaim) showed better performance than imported cement (Ismnta and Torab alsabia) in most tested chemical and physical properties .Kubaisa cement showed 34.1 % , 35.5 % higher compressive strength compared with Ismnta cement at 3 and 7 day respectively and lower loss on ignition and insoluble residue . The major compounds of Kubaisa cement were nearest to those in typical cement. For sulfate resisting cement , Al-qaim cement showed 13.3 % higher compressive strength at 7 day and lower percentage of C3A (1.95%) . Torab alsabia cement exceed the limits of Iraqi standard I.O.S No.5 1984.

Estimation of Suitable Grade Value for Stopping Sight Distance Computation on Vertical Curves

Ahmed H. Farhan

Iraqi Journal of Civil Engineering, 2008, Volume 5, Issue 10, Pages 90-101
DOI: 10.37650/ijce.2008.14122

Abstract The purpose of highway geometric design is to provide safe and economical highways. One of the utmost important geometric design element for safely travel that should be satisfied is visibility on designed road. This can achieved by providing adequate sight distance in both horizontal and vertical alignments. Minimum sight distance that should be provided at all points along highway is stopping sight distance SSD. In the design of vertical curves AASHTO's Geometric design Policy uses the sight distance requirement as a major criterion in curve length determination. Moreover, sight distance has great effect on highway constructional cost because more required sight distance means more vertical curve length, which in turn means more earthwork materials. Consequently, safety and economics can be considered as a major criterion in design of highways. The AASHTO's model involved design speed, perception-reaction time, and frication factor as a parameters used for SSD computations on level sections. On inclined surfaces, an additional parameter denoted by (G), which reflect grade of sloped surface on SSD. In the present paper a new approximate methodology and Equations are formulated though which a suitable design grade value can be estimated on vertical curves where the grade not constant then utilizing this value to compute SSD on these curves and hence compute vertical curve length corrected for grade effect. Generalization of present methodology is carried out by derivation a general mathematical solution. From these derivations it has been found that the suitable grade value for Type I and Type III (initial and final grade are descending and ascending) is half of the largest grade among G1 and G2. While the design grade value is the average value of G1 and G2 for Type II and Type IV (both grade are descending or ascending). Comparison with other grade estimation on vertical curves suggestions showed that the present methodology produces more reasonable and economical value because the obtained length is no longer to be uneconomical as compared with other suggestions. At the same time it provides a safe value used in all design cases those reflects the actual case as compared with other suggestions those ignored or reduced the effect of grade.

OPERATIONAL ANALYSIS OF RAMPS ON EXISTING FREEWAY

Asma Thamir Ibraheem

Iraqi Journal of Civil Engineering, 2008, Volume 5, Issue 10, Pages 102-132
DOI: 10.37650/ijce.2008.14125

ABSTRACTAn operational analysis is an analytic evaluation of operation on an existing freeway ramps. In this case, all traffic and roadway conditions must be specified. The output of operational analysis is an estimate of the level of service for the ramp in question and of the approximate speed and density at which the traffic stream operations.A ramp is length of roadway providing an exclusive connection between two highway facilities. On freeways, all entering and exiting maneuvers take place on ramps those are designed to facilitate smooth merging of on-ramp vehicles into the freeway traffic stream and smooth diverging of off-ramp vehicles from the freeway traffic stream onto the ramp.The aim of this paper is the operational analysis of ramps on existing 6-lane freeway. This analysis involves the consideration of known freeway of Mohammed Al-Kasim freeway in Baghdad city. Given known geometric roadway conditions and projected traffic conditions, the operational analysis yields an estimate of the level of service and of the speed and density of the traffic stream. This paper has described the procedure for determining the level of service on Mohammed Al-Kasim freeway ramp sections as presented in the Highway Capacity Manual (HCM, 2000). Levels of service are determined for all ramps of the freeway using )HCS2000( software. Level of service of all ramps are similar at AM and PM peak hour periods, because the data was collected under ordinary traffic conditions.