TransCAD and GIS Technique for Estimating Traffic Demand and Its Application in Gaza City

Transportation planning relies on traffic demand forecasting process. The conventional process is impeded by extensive amount of socioeconomic data. One of the most widely-used models which mitigate this problem is the TransCAD Model. This model is rarely used in Gaza Strip for traffic demand forecasting, and most of the practices depend mainly on a constant growth rate of traffic. Therefore, the main objective of this research is to apply this model in Gaza City for traffic estimation. This model estimates the origin-destination matrix based on traffic count. The traffic count was carried out at 36 intersections distributed around Gaza City. The results of traffic flow estimation obtained from TransCAD are assigned to the Gaza maps using the GIS techniques for spatial analysis. It is shown that the most congested area at present is the middle of the city especially at Aljala-Omer Almokhtar intersection. Therefore, improvement scenarios of this area should be carried out. The results of calibration of traffic flow estimation show that the differences between the estimated and the actual flows were less than 10%. In addition, network evaluation results show that the network is expected to be more congested in 2015. This work can be used by transportation planners for testing any network improvement scenarios and for studying their network performance.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Seismic Response and Stability Analysis of Single Hinged Articulated Tower

Offshore structures subjected to wave, earthquake or wind loads or a combination of these loads show non-linear transient behaviour. As oceanic waves are better modelled as stochastic process, there is a need to investigate the stochastic stability of flexible offshore structures as well. Present study has been carried out to determine seismic response of Single Hinged Articulated Tower (SHAT) under different categories of wave loads and earthquake followed by its dynamic stability analysis. Different phases of wave/earthquake loading on SHAT have been explored to investigate dynamic instabilities existing during each phase. Two dimensional phase plots have been used to identify phases of dynamic instability existing within the responses of SHAT under various conditions of loading.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Influence of the Elastic Modulus of the Soil and Concrete Foundation on the Displacements of a Mat Foundation

The objective is to highlight the soil-structure interaction particularly the influence of the rigidities of the soil and the concrete on the subgrade reaction (k) and the displacements of the mat foundation subjected to vertical loads. From plate theory and the soil-structure interaction, the general equation is reached. This equation depends more on the subgrade properties than the concrete foundation properties. Consequently, the behavior of the mat foundation is more influenced by soil properties than the concrete.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Safety Assurance for Challenging Geotechnical Civil Engineering Constructions in Urban Areas

Safety is the most important aspect during design, construction and service time of any structure, especially for challenging projects like high-rise buildings and tunnels in urban areas. A high level design considering the soil-structure- interaction, based on a qualified soil investigation is required for a safe and optimised design. Due to the complexity of geotechnical constructions the safety assurance guaranteed by the 4-eye-principle is essential. The 4-eye-principle consists of an independent peer review by publicly certified experts combined with the observational method. The paper presents the fundamental aspects of safety assurance by the 4-eye-principle. The application is explained on several examples, as deep excavations, complex foundation systems for high-rise buildings and tunnel constructions in urban areas. The experiences made in the planning, design and construction phases are explained and for new inner urban projects recommendations are given.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Experimental Behavior of Partially Prestressed High Strength Concrete Beams

 It currently becomes more desirable as it has better mechanical properties and durability performance. Major defect of fully prestressed concrete is its low ductility; it may produce less alarming signs than ordinary reinforced concrete via smaller deflection and limited cracking. Therefore, partially prestressing is considered an intermediate design between the two extremes. So, combining high strength concrete with partial prestressing will result in a considerable development in the use of prestressed concrete structures regarding the economical and durability view points. This study presents the results of seven partially prestressed high strength concrete beams in flexure. The tested beams are used to investigate the influence of concrete compressive strength, prestressing steel ratio and flange width on the behavior of partially prestressed beams. The experimentally observed behaviors of all beams were presented in terms of the cracking load, ultimate load, deflection, cracking behavior and failure modes.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

3-D Modelling of the Confederation Bridge Using Data of Full Scale Tests

Long-span bridges are special structures that require advanced analysis techniques to examine their performance. This paper presents a procedure developed to model the Confederation Bridge using 3-D beam elements. The model was validated using the data collected before the opening of the bridge to the public. The bridge was instrumented to conduct fullscale static and dynamic tests. The static tests were to measure the deflection of the bridge pier while the dynamic tests to measure the free vibrations of the pier due to a sudden release of the static load. Confederation Bridge is one of the longest reinforced concrete bridges in the world. It connects the province of Prince Edward Island and the province of New Brunswick in Canada. Due to its strategic location and vital role as a transportation link between these two provinces, it was designed using higher safety factors than those for typical highway bridges. After validating the present numerical model, a procedure was developed to evaluate the performance of similar bridges subjected to traffic and seismic loads. It is of interest to note that the foundation stiffness and the modulus of elasticity of the concrete have significant effects on the structural responses of the Confederation Bridge.

Website:  http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Similarity Study on Snowdrift Wind Tunnel Test

The model for snowdrift wind tunnel test needs to be similar with the prototype. Based on detailed analysis in aspects of geometry, kinematics and dynamics, the major similarity parameters that need to be satisfied are gained. The contradiction between the Reynolds number and Froude number as well as the problem of time scale is introduced, and the selections of the model parameters are specified. Lastly, an example of snowdrift wind tunnel test by adoption of quartz sand as the model of snow grains is presented. The flow field and the snow distributions on a typical stepped roof were investigated. The results show that the flow filed characters are in good agreement with the field observations, and the stepped roof snow depth distributions are basically consistent with the observation results.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Intrinsic Compression Behavior of Remolded and Reconstituted Clays-Reappraisal

Evaluating the impacts of soil structure on mechanical behavior for natural sedimentary clays is an important issue in geotechnical engineering. Burland introduced void index for normalizing the compression curves of various remolded and reconstituted clays to obtain the intrinsic compression line, which provides a reference framework to assess the in-situ compression behavior. However, it does not quantitatively account for the effects of initial water content on compressive behavior of remolded and reconstituted clays and the initial water contents of clays are not always limited to 1.0 - 1.5 times the liquid limits defined by Burland. A modification based on collected tests data was presented on the expressions of  and  defined by Burland. Extensive oedometer test data were also collected on various remolded and reconstituted soils with distinct liquid limits and initial water contents to verify the validity of modified expressions. A normalized compression line deduced by intrinsic compression line is proposed in the e-log p plot, which can be used to evaluate the effects of soil structure quantitatively on the intact compressive behavior for natural sedimentary clays.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Significance Analysis of Flexural Behaviour of Hybrid Sandwich Panels

Two different types of natural fibers reinforced plastics (NFRP) laminate were incorporated into the new sandwich panel as an intermediate layer. The significance analysis in this research has been carried out using analysis of variance (ANOVA). As the aim of the analysis is to select the most appropriate natural fiber composites for the intermediate layer, the experiments were arranged as a single factor experiment in which 3 levels of a factor have been examined. The factor refers to the type of intermediate layer used in the sandwich panel. The result of this study shows that the incorporation of intermediate layer has significantly enhanced the load carrying capacity of the sandwich panels.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Pedestrian Countdown Signals: What Impact on Safe Crossing?

Crossing episodes of over 5000 pedestrians were videotaped and analyzed using multivariate statistical methods. Details of timing of pedestrian crossing as well as information about vehicular traffic and signal timing were carefully coded for each pedestrian. Significant safety benefits of the PCS system were found on the long crossings over a street with high vehicular volumes: most pedestrians were able to effectively increase their walking speed to complete their crossing without committing the exit violation—even if they have already committed the entry violation. However, on the short crossing with light vehicular traffic, PCS was generally ineffective in preventing the entry violations from becoming exit violations. Over there, many pedestrians felt safe enough to walk over a short crossing with no apparent vehicular traffic in sight instead of waiting for a green signal. The length of crossing and volume of interfering vehicular traffic were consistently found the most significant variables affecting the crossing violation rates of different categories of pedestrians. Crossing violation rates were the highest for runners, bicyclists and older males. Crossing violation characteristics were found to be consistent over time.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

The Effect of Incorporation of Ferrite Nano-particles on Compressive Strength and Re-sistivity of Self-Compacting Concrete

The data of XRD clarified that the sample was formed in single phase spinel structure without any extra peaks indicating non-existence of any secondary phase. The HRTEM micrograph indicated that the particles were in an agglomerated state due to the absence of surfactant and high magnetic properties of Mn-Ferrite nanoparticles. The mechanical properties were measured at different ratios of nano-Ferrite to concrete. The obtained values of mercury intrusion porosimetry (MIP) indicated that the addition of Mn-Ferrite nanoparticles increased the compressive strength and decreased the total intrusion volume. This was due to the rapid consuming of Ca(OH)2 which was formed during hydration of Portland cement especially at early ages due to the high reactivity of MnFe2O4 nanoparticles. Moreover, MnFe2O4 nanoparticles recovered the particle packing density of the blended cement, leading to a reduced volume of pores in the cement paste.

Website:  http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Seismic Capacity Assessment of Existing RC Buildings in The Sudan by Using Pushover Analysis

The objective of this paper is to assess the seismic performance of existing RC buildings in The Sudan. Four typical buildings were investigated using pushover analysis according to ATC-40. They were designed according to the Regulations for earthquake-resistant design of buildings in Egypt (ESEE) and International Building Code (IBC2012). Results showed that the buildings designed considering by ESEE and IBC2012 loads were found adequate and satisfied the Immediate Occupancy (IO) acceptance criteria according to ATC-40. The comparison of the pushover curve shows that the stiffness of frames is larger when using ESEE Regulations compared to the IBC2012 design. This means that ESEE design procedure provides a greater capability to resist seismic load than the IBC2012 design.

Website:  http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Applications and Prospects of Fiber Reinforced Concrete in Industrial Floors

Upon the view of this work, industrial floor is a vital structure due to its relation to quality of production, labor comfort, and human health. Flooring costs may reach 20% of single-story building construction expenditure, and the consumption of concrete for floors may come to 40% - 50% of the total size of concrete. Thereby, the efficient design of floor will reduce materials consumption and labor, and will increase the endurance of the floor. Fiber reinforcement reduces the thickness of the subfloor about 20% - 30%, hence enabling to reduce the consumption of cement and fillers. The use of fiber meshes will enable to save 30% - 40% of steel. Despite the flexible use of fiber in concrete reinforcement saves effort and money, still fiber reinforced concrete is lacking additional regulations in Jordan.

Website:  http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Evaluation of Water Distribution Jointed Pipe Networks under Transient Ground Motions

wave propagation. First, using finite element method and solid elements, different kinds of currently used connections in the network are modeled, and their nonlinear behavior in all directions is obtained. Second, a 950-meter long network consisting of ductile iron pipes segments of 6-meter length and springs characterizing the connections, are modeled using beam elements. Three-component displacement record of the Tabas earthquake is applied to the network considering the time lag between support inputs, and the nonlinear soil-pipe interaction. The record is applied once in North-South direction and once in East-West direction with different wave propagation velocities. Results of interest such as stress values and rotations at various points of the network are then obtained, and critical points are introduced in each direction. Results show that the points other than the critical ones at the network intersections remain elastic.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Effect of Using Stone Cutting Slurry Waste (Al-Khamkha) on the Compaction Characteristics of Jerash Cohesive Soil

The aim of this research is to study the effect of using (Al-KHAMKHA) is stone cutting slurry waste local name in JORDAN on the unit weight and moisture content of Jerash cohesive soil Al-Khamkha which is the local name of the stone cutting slurry waste which is produced during the cutting operation, This water carries large amounts of stone powder, which leads to complex nature of environmental problem so these waste material needs to be utilized meaningfully in economic way. The degree of compaction of a soil is measured in terms of its dry unit weight Al-Khamkha mixed with Jerash cohesive soil at different amount ranges from 0%, 5%, 10%, 15%, up to 50% and compaction characteristics of Jerash cohesive soil without and with different amount of Al-Khamkha was studied. This investigation show that as the amount of Al-Khamkha increase from 0% to 15%, the dry unit weight of Jerash cohesive soil increase from 14.4 KN/m3 at 0% of Al-Khamkha to 16.5 KN/m3 at 15% and after that .any increase of Al-Khamkha decrease the dry unit weight. On the other hand, the optimum water content of the Jerash cohesive soil was increases with increasing the percentage of Al-Khamkha on the cohesive soil.

Website:  http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Computational Finite Element Modelling of Structural Behaviours of Precast Sandwiched Foamed Concrete Slab

The structural behaviour of Precast Lightweight Foamed Concrete Panel (PLFP) under flexural load is investigated by using ABAQUS 6.13. The PLFP is made up of two Whyte’s with a polystyrene insulator placed in between them using a double shear truss connector of diameter 6mm placed at an angle 45°. The panel is reinforced with both vertical and horizontal steel reinforcement of 9 mm diameter. Four panels with varying dimensions are simulated to investigate their Ultimate Strength and Load-deflection profile. The results show that the length to thickness ratio of the panel is the major contributing factor to the ultimate strength of the PLFP. From the load deflection curve, the panel with the least deflection has the highest thickness which also results in a high ultimate strength recorded at 34.43 KN.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Comparative Studies of Steel, Bamboo and Rattan as Reinforcing Bars in Concrete: Tensile and Flexural Characteristics

The beams were subjected to centre-point flexural loading according to BS 1881 to evaluate the flexural behaviour. The YS of bamboo and rattan bars were 13% and 45% of that of steel respectively, while their UTS were 16% and 62% of that of steel in the same order. The elongation of bamboo, rattan and steel were 7.42%, 10% and 14.7% respectively. The natural rebars were less than the 12% minimum requirement of BS 4449. The load-deflection plots of bamboo and steel RC beams were quadratic, while rattan RC beams had curvilinear trend. The stiffness of bamboo RC beams (BB) and rattan RC beams (RB) were 32% and 13.5% of the stiffness of steel RC beams (SB). The post-first crack residual flexural strength was 41% for BB and SB, while RB was 25%. Moreover, the moment capacities of BB and RB corresponded to 51% and 21% respectively of the capacity of steel RC beams. The remarkable gap between the flexural capacities of the natural rebars and that of steel can be traced not only to the tensile strength but also the weak bonding at the bar-concrete interface. It can be concluded that the bamboo bars are suitable rebars for non-load bearing and lightweight RC flexural structures, while more pre-strengthening treatment is required more importantly for rattan for improved interfacial bonding and load-carrying capacity.

Website:  http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Compressive and Flexural Behaviour of Unstressed Concrete Substructure in Cassava Effluent Contaminated Soils

The rate of deterioration is affected by the loading condition, and more importantly the physical and chemical nature of the host environments. This paper reports the experimental investigation of unstressed concrete substructure in the natural (uncontaminated) and cassava’s hydrocyanide effluent-polluted soils on the compressive and flexural strengths of buried concrete specimens for a maximum of 84 days. The compressive strengths of the cubes were tested every 7 days until the 84th day, while the beams were only subjected to third-point loading flexural tests at age 84 days. The compressive strength of concrete specimens in the two soil environments increased, though the trend was lower in the polluted soil. The strength reduced by 2.50% to 9.47% between the 7th and 28th days, but steadily between the 28th and 84th days with strength loss of 9.95% (COV = 2.64%). The load-deflection curves were quadratic for the beams in the two geo-environments. The beams in cyanide-polluted soil lost 34.5% of its flexural stiffness, while its loss of load-carrying capacities at the first crack and ultimate failure was 15.8% and 20% respectively. Higher degree of deterioration is certain for loaded concrete substructures in similar conditions. Hence, prior knowledge of soil chemistry is crucial to determining suitable concrete grade and nominal cover for durable substructural elements.

Website:  http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Influence of Mechanical Properties of Concrete and Soil on Solicitations of Mat Foundation

These two parameters are dependent on the geometrical and mechanical characteristics of the system. Results of this study show a sensitivity of solicitations to variations of geometrical and mechanical characteristics of the model. Although solicitations in the plate are sensitive to mechanical properties of concrete, these solicitations are strongly influenced by the mechanical and geometrical characteristics of the soil mass. However, it should be noted that the influence of Eb is denoted in the center of the plate whereas the Es feels almost in the same manner over the entire extent of the plate. This study also shows that for the same load cases, the values of the torsion moment and shear stress are not significant those of bending moments and normal stresses, respectively.

Website:  http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/

Analysis of the Probability Model of Wind Load on the Offshore Wind Turbine

According to the actual measurement data, probability models of horizontal wind load were obtained based on wind velocity statistic and power spectral density function of fluctuating wind velocity through stochastic sampling and using spectrum analysis method. Through the comparison of two models, probability models of horizontal wind load based on probability models of fluctuating wind velocity were obtained by revising the mean and variance of fluctuating wind velocity. Results show that the variance takes lower value when the power spectral density function of fluctuating wind velocity is used to obtain the probability model of horizontal wind load. The quadratic term of fluctuating wind velocity takes a small contribution value in total wind load with almost no contribution to the model of horizontal wind load. It is convenient for practical engineering to obtain the models of horizontal wind load by using probability models of fluctuating wind velocity.

Website: http://www.arjonline.org/engineering/american-research-journal-of-civil-and-structural-engineering/