—Transport mode choice in Alexandria has radically changed during the last decades, since many trips were shifted from public transport to private transport and informal public transport. This research aims at analyzing the sensitivity of transport mode choice in Alexandria under different transport policies and assess the impact on modal shift to public transport. For that aim, a Multinomial Logit Model for Alexandria has been developed, calibrated using Biogeme Software. Having validated the calibrated model, the behavior of modal split under different policies is analyzed. The proposed transport policies includes improving public transport attributes and/or increasing trip cost for other transport modes. The analyses results reveal that improving current public transport trip time and trip cost have moderate and minor effect on modal shift to public transport share respectively. Improving public transport utility constant has a significant effect, which can be achieved by introducing reliable, attractive, efficient and frequent public transport system. The impact of increasing private car, taxi and collective taxi trip cost on modal shift to current public transport is minor. The combination between the proposed push and pull policies may achieve a modal shift to public transport mode effectively.
The response of a structural frame to earthquake ground motion is predicted using the structural mixture theory (SMT). This research presents four different case studies to evaluate the performance of the structure mixture theory in the earthquake response analysis of buildings. In the first case study, the actual earthquake responses of the two-story reinforced concrete building, which was tested at the University of California at Berkeley, were compared to those obtained using the SMT. In the second case study, the seven-story reinforced concrete building, which was tested as a part of the US-Japan Cooperative Earthquake Program, was considered. The third case study is about the calculation of nodal deflection amplitude with SMT and comparison of the results obtained from Wilsonmethod. In the fourth case study, the observed earthquake response of a nine-story steel frame building during San Fernando earthquake is compared with the SMT numerical results of the structure. All the case studies showed that the structure mixture theory (SMT) results were very close to the experimental and numerical results. The mean differences between the maximum roof displacements obtained experimentally and numerically in all of the four case studies and those obtained using the SMT were found to be equal to 3.5%, 3.2%, 2.4% and 5.6% respectively. The structural mixture theory is valid for multipledegree-of-freedom structures under the type of ground motions used in this study, and it appears to be applicable to systems with linear or nonlinear behavior. Keywords— Earthquake ground motion, Structure Mixture Theory, nodal deflection amplitude
Natural fibers, including the Bamboo, are environment friendly materials. They require a low degree of industrialization and a small energy for their processing and production, and hence the total fabricating cost is also low. The main purpose of this paper is to cover the lack of information about Bamboo; its mechanical properties, interaction with concrete, strength and durability, and to investigate its validity of replacing steel as a reinforcement of concrete beams. This possibility is investigated through experimental results of bamboo reinforced concrete beams compared with others reinforced using steel. The experimental results were verified and expanded using the FE package called ANSYS. In this research, the Bamboo was used without any treatment or stirrups. It was found that untreated Bamboo must not be used as reinforcement in concrete beams, although its mechanical properties may be considered as comparable to steel.
Freezing-thawing of various materials submerged in saline water was tested for one year. The experiment was done by a freezer where the individual specimen was submerged in 20% concentrated Magnesium Sulphate solution. It is already developed that fly ash geopolymer products show better strength and durability in compare to conventional cement product. This paper is further focused to the long-term durability of fly ash geopolymer with the incorporation of another postindustrial recycled material like blast furnace slag as supplement. The outcome of the research is that the drop of compressive strength on BGP (Blended Geopolymer) specimens are remarkably less compare to OGP (Ordinary Geopolymer) specimens. The important result was that alternative freezing and thawing did not affect much on strength of BGP specimens but had a considerable effect on strength of OGP specimens. Basically the reason for such a behavior is that the structure of OGP is unable to resist the tension caused by freezing of pore water due to volumetric increment. But for BGP the amount of water present in the pore is very less. Thus, more water confined inside the OGP causes cracking which allows more water absorption after every freezing – thawing cycle.
There is an enormous growth in number of skew bridges or flyovers; especially in urban and developing cities. Due to ease in construction and constraints of space availability in cities; highway interchanges or grade separators, the skewed slab bridges are adopted instead of conventional straight slab bridges. The present paper discusses the typical skew slab behaviour emphasize on lateral live load distribution, skew angle influence and application of finite element method to determine the stress parameter. The objective of this study is to understand the pros and cons of behavior of skew slab bridges from the available literature.
Dolmush is a shared taxi system, which has a fixed route. This paratransit system is very popular in Turkey for a long time. The system offers cheap and comfortable trips like a private car in city centers. But the system has low capacity by comparison to other public transit systems and many dolmush drivers cause traffic problems in city center. Therefore many Turkish municipalities try for transition from dolmush to taxi. But there is no prediction study about “after transition”. Many passengers can prefer using of their private car and therefore traffic and parking problems can increase in city center. Because dolmush isn’t an unproductive alternative of bus system, it is a very productive alternative of private car usage. Therefore, it needs a detailed study about after transition.
Prevalent governmental guidelines issued by US General Services Administration (GSA) and US Department of Defense (DoD) are widely used for design of structures against progressive collapse. Significant studies have been carried out for progressive collapse of steel and reinforced concrete framed structures according to these guidelines. These guidelines are also being constantly updated based upon the outcome of researches being carried out worldwide. Recently, DoD guidelines were updated in 2005 and 2009; whereas, GSA was following its 2003 guidelines. Major discrepancies were there between the 2009 version of DoD and 2003 version of GSA. To remove these discrepancies, GSA recently updated its guidelines in 2013. In the present study, the progressive collapse study of nine storied rigid and semi-rigid jointed steel frames has been carried out according to (GSA 2013) and (GSA 2003). Subsequent changes in modeling parameters and acceptance criteria from (GSA 2003) to (GSA 2013) and their influences in design are discussed in the present study.
In the recent years, tremors resulting from earthquakes in Bangladesh were felt by occupants in many buildings. As a result, the structural integrity of these buildings has become a major concern. To address the issue, in this study time history analysis has been carried out to investigate the structural response of two proposed 6 and 9-story apartment buildings. Each building of this study has a different floor layout plan. The seismic performance is observed for different earthquake data with different frequency content. Both static (considering p-∆) and dynamic analyses were carried out. From this study it is observed that building drifts exceeded the drift criterion set forth in the Uniform Building Code 1994 (UBC94). This study concludes that while the two buildings were designed to comply with requirements for wind and earthquake load static in nature, they can be vulnerable to damages caused by dynamic seismic load due to excessive lateral drifts. The primary focus of this study was to investigate the displacement profile and inter-story drift from time history analysis that have been compared with the values from static analysis. Comparison visualizes, the structures designed considering static analysis may be failed in a dynamic situation. So new design criteria may be proposed considering dynamic analysis to minimize the drift effect on structure up to acceptable limits.
One of the main problems of conventional concrete under water is the high percentage of material loss due to the washout of cement paste. This research presents the influence of anti washout admixture (AWA) and coarse aggregate types on various properties of self-flowing underwater concrete. AWA is water soluble organic polymer, which increases the cohesion of concrete, in a way that significantly reduces the washout of the finer particles, i.e., the cementitious material and sand from fresh concrete when it is placed underwater. The work involves three groups with the total number of twenty-four self-flowing underwater underwater-concrete mixes. The test program was designed and arranged to consider the effect of four different parameters as follows; AWA (0.0, 0.2, 0.3, 0.4 and 0.5%) by weight of cement, cement contents (450, 500 and 550 kg/m3), type aggregates (steel slag, crashed dolomite, gravel) and fine materials (content and type). All concrete mix contains high-range water reducing 4% by weight of cement. The fine to coarse aggregate was 1: 1. The concrete mixtures were tested for slump flow, blocking Ratio, GTM screen stability, air content, weight loss method that is the plunge test CRDC61 which is widely used in North America, and compressive strength. Compressive strengths were evaluated at 7 and 28 days’ age for under-water casting as well as air casting conditions. Test results indicated that the use of an AWA facilitates the production of self-flowing underwater concrete with the added benefit of lower washout loss.
Vegetal products are increasingly gaining ground in the composition of industrial and construction materials given their cost effectiveness and the growing concern about issues such as environmental protection and sustainability. Arabic Gum Biopolymer (AGB), a wild plant product found mainly in Sudan and also produced in other tropical African areas, has been widely used in various industries. Whereas its utilization is very limited in the construction sector, there is a clear indication that ABG has a potential for being an effective additive to concrete mixes that would improve fresh and hardened concrete properties. The aim of the present work is to evaluate the influence of AGB on the physical and mechanical properties of ordinary concrete at various ages including workability and air content of the fresh mix and porosity, capillarity and compressive strength after hardening.
The current research presents a quick method for estimating the lateral stiffness and torsional stiffness of 3D MRF (moment-resistant frame) structures, considering irregular moment frames. This study also provides a method for calculating story displacement and rotation and natural frequencies with respect to different lateral load patterns. This study proposes a method for calculating lateral and torsional stiffness for each frame in two directions, and then converting the stiffness of all frames to one frame to obtain the deformation and natural frequency for two directions. The basic idea of the proposed innovative method was developed through the force method to obtain the lateral deformation and stiffness of 2D building structures. Then, the mentioned procedure was expanded into 3D building structures. Some examples have been made to compare the latter method with linear analysis. The results showed that the suggested method can capture 3D dynamic characteristics with accuracy compared with linear analysis.
This Research paper reflects the seismic importance of Shear walls in RC frames. A proposed 8-storey symmetric (rectangular in plan) RC building in Kashmir (INDIA) is chosen as model in this study. The building is first modeled using Indian Standard Code of Practice (IS 875, parts I-V) specified for school occupancy and then designed for gravity and lateral loads manually using Moment Distribution Method (MDM). The results from MDM were fed to a FORTRAN based program developed by the University of Buffalo called IDARC-2D to carry out inelastic two dimensional analyses on selected frame (critical one) from the building. This program is able to compute what is known as ‘structural damage index’ which is a way of quantifying numerically the seismic damage suffered by buildings. The damage indices such as base shear, storey drift, displacement etc. are computed for each storey by IDAREC-2D using the modified ELCENTRO (1940) design response spectra for critical frame without and with shear walls (at different locations) separately. The damage indices for each storey, with and without shear walls were tabulated and plotted on a same scale for comparison study and discussion. Conclusions are drawn from the work and important recommendations on the basis of results are drawn from the comparisons and conclusions.
India is rapidly growing country and many road structures are in constructing phase. It is required to be compliance with quality assurance for prevent failure and long performance. Quality assurance work involves the compaction parameter but from recent years, it is moving to a modulus-based method. The aim of this paper is to evaluate the elastic modulus of flexible pavement using portable light weight deflectometer and develop a relation with density and moisture content for quality assurance. In situ test measurements are taken on 40 test locations, the LWD used for determine elastic modulus, core cutter method used for density and samples are tested for moisture content in a laboratory. Elastic modulus is back-calculated using LWDmod software. The multiple linear regression relation shows a coefficient of determination (R2) of 0.491 and trend line of elastic modulus increases with an increase in bulk density and decrease in water content.
Steel structures with special steel eccentric bracing frames are one of the systems widely employed to resist lateral loads. Given the significance of construction costs and its association with the selected structural system, number of the floors, beam span length, location of columns, and the soil type, this paper investigates the optimum values of these parameters. The aim of the present article is to find the optimal topology with respect to architectural requirements and applicability considerations. To this end, models with hybrid structural systems with simple steel frames and eccentric bracing with special ductility level for 5, 10, and 14 floors were selected. The selected models were assumed with equal area and two different soil types. In order to provide parking space based on the urban development regulations, models were considered with span length of 5.6, 7.5, and 11.2 meters to locate 2, 3, and 4 cars between columns respectively. Having analyzed the models and designed structural members and foundations, amount and cost of the building materials were estimated based on the available rates and the results were compared using figures. The most economical structures were proposed for both soil types and for the number of floors.
Cloud computing refers to use of virtual servers where users access stored data through an internet connection. It has become an innovative model for delivering IT infrastructure, applications and data management. It shifts the emphasis from static, stand-alone applications to dynamic, shared environments, dynamically allocated among various tasks and accessed via a network. In construction projects, construction managers spend a significant portion of their time gathering project data, assessing production rates, communicating with project participants and tracking project quality. Executing those tasks manually reduces efficiency and can result in less effective project management operations. In order to improve efficiency of information process flow, various types of Project Management Information Systems (PMIS) have been introduced to construction projects. This paper is an attempt to structure the data base through cloud computing and also to develop a Project Management Information System (PMIS) through cloud computing for a power plant project.
This paper presents an experimental study on cement mortars with different originated pumice aggregates (PA) in order to investigate PA effects on some properties of mortars. Natural sand (NS) was also used to prepare control mortars as reference mix. With this purpose, experiments for aggregate characterisation were conducted and additionally compressive strength, flexural and splitting tensile strength tests were performed on mortars. Results obtained throughout experimental study were analyzed and compared. Replacement of PA with NS led to decreases in mechanical properties of mortars. However, these reductions were differentiated due to the different properties of aggregates. The investigation undertaken also demonstrated the possibility of pumice aggregates in production of structural lightweight mortars. Keywords—pumice aggregate, compressive strength, tensile strength; lightweight mortar
— The study evaluates forecasting of groundwater level for short period of data by utilizing the standard artificial neural network (ANN) model, trained with two back propagation (BP) training algorithms namely Levenberg-Marquardt (LM) and Gradient Descent with Momentum (GDM). Data of five wells, Annual rainfall, Temperature, Relative humidity and river stage are chosen as input parameters.The model efficiency and accuracy were measured based on the root mean square error (RMSE) and regression coefficient (R).R-values approach towards the unity for most of the wells in LM method. LM method is recommended for forecasting ground water level for short duration of data and also it is anticipated that this method will give fairly accurate result for long duration of data under consideration. In case of constraint on data availability mentioned above, the LM Method is found to be suitable for ground water forecasting even when we take river water level as one of the inputs in ANN model.
Wind energy is one of the most consistent sources of renewable energy and there is a strong, steady and unhindered wind flow in offshore resulting in higher energy generation. In addition there are benefits of no size restrictions and land utilization. The design of the offshore wind turbine is affected by several factors and needs to be economized for mass implementation. The presented work considers the effect of different modes of floater displacements on the offshore wind turbine loading to develop a safe, stable and economical design. Partially fixed turbine was subjected to wind and base displacement. Six displacements were considered using Sway-Rocking Model and their responses were analyzed. Comparisons of the results with the Fully Coupled Floating Offshore Turbine System were also conducted which indicated that among the surge, heave and pitch displacement modes. Pitch was the most important for floater motion and governed the design of an economical floater system. It was also observed that displacements in surge case were 1/3rd of the displacement in fully coupled case while they were half in case of heave; furthermore the turbine loads for all cases were much lower as compared to the fully coupled case.
Fiber Reinforced Polymer (FRP) bars are gaining increasing acceptance in construction industry particularly in aggressive environments. Enhancing the serviceability behavior is of main points that still require further investigations. In this paper a solution for the bond and serviceability enhancement is proposed through modifying the bar shape and enhancing the concrete properties. Newly developed square glass-FRP (GFRP) bars were fabricated, tested, and the behavior was compared with circular GFRP and steel bars. The physical and mechanical properties of GFRP square and circular bars are presented. An experimental study of oneway concrete slabs reinforced with the developed square and circular GFRP and steel bars was performed. A total of 9 full-scale RC slabs were fabricated and tested up to failure to study the effect ofthe test parameters: type of reinforcement (steel versus GFRP), bar cross section shape, concrete compressive strength, reinforcement ratio of longitudinal bars, and the use of polypropylene fiber ratio. Based on the experimental test results, it was found that the bond strength of GFRP bars increased by increasing the polypropylene fiber. Also, changing the bar surface area from circular to square cross section, resulted in a slight increased in the bond strength. In addation, the behavior and ultimate flexural loads of concrete slabs reinforced with GFRP square bars were improved compared with concrete slabs reinforced with GFRP circular bars. Increasing the concrete compressive strength, resulted in improvement of the behavior of concrete slabs with GFRP square bars.
Among all different phases of building lifecycle, the operation & maintenance is the phase in which the project owner need to spend maximum in terms project time & cost. Facility Management (FM) thus becomes an integral and very important part for any organization of real estate sector, health care sector, education sector and hospitality sector. If the new technology like Building Information Modeling (BIM) is used for such work, it can improve the efficiency of this function. Thus this study is an attempt to identify the Key Performance Indicators (KPI)s that affects the usage of BIM as a FM tool and also to develop a process framework which would act as guide for the users interested in using BIM as FM tool. Based on a primary data questionaire survey responded by 69 respondents, 41 KPIs were identified. These 41 KPIs consisting of both “leading” and “lagging” indicators were finally reduced to 15 KPIs through factor analysis. Finally, selected 15 indicators were divided into 5 different groups or components using principal component analysis (PCA) method of factor analysis. The components so formed, were logically sequenced to formulate the process diagrams which would facilitate the clients, consultants and users to develop awareness about the usage of BIM as FM tool.
