Published by the Institute of Building and Roads Research.
Institute of Building and Roads Research-University of Khartoum
Evaluation of the Behavior of Sudanese Soils using Cone Penetration Test (CPT) Method; The State of the Art
This paper reviews the main findings and conclusions drawn from research studies that dealt with the application of the CPT method for estimating important geotechnical characteristics of Sudanese soils. Great efforts were made in previous research works to develop correlation relationships between CPT data and soil parameters determined from laboratory testing of samples obtained from different states in the country. Generally, the CPT has proved to be useful in the characterization of studied soil behavior. Sound relationships have been proposed for predicting the SPT, undrained shear strength, compressibility, over-consolidation ratio and swelling potential of local soils from CPT data. It has been shown that the relationships between CPT and the soil parameters considered are affected by some factors such as the type, moisture condition and stress history. The relationships based on CPT proposed for the SPT and undrained soil strength have been revised and modified using further databases and more rational analysis techniques made available in recent times. The developed correlation relationships are useful for evaluation of important soil parameters that are needed for the design and construction of foundations in future engineering projects.
الحقوق الفكرية (c) 2022 Journal of Building and Road Research
It is with great sadness and deep sorrow that the Editorial Board of the “Journal of Building and Roads Research” mourns one of its active and well respected members, the late Professor AbuBakr A. Wahab M. Salih, Professor of Civil Engineering, University of Khartoum who passed away on Friday 25th September 2020, leaving behind him a space that can hardly be filled.
Editorial Board of the “Journal of Building and Roads Research
الحقوق الفكرية (c) 2021 Journal of Building and Road Research
Roadmap for Implementation of Building Information Modelling in the Construction Industry in Sudan
The importance of the building information modelling (BIM) adoption has been increasingly recognized by the construction industry in Sudan and all over the world. It is facing many barriers and challenges to increase productivity, efficiency, and quality. This paper aims to develop a roadmap to facilitate BIM implementation in Sudan and to ensure a smooth transition from traditional working methods to BIM technology focusing on three factors: technology, process, and people. The developed concept map and roadmap in the paper give tools and guidelines for assessment of the organisation by identifying key challenges and actions to be considered in order to implement BIM in Sudan.
Finite Element Analysis of Reinforced Concrete Beams Strengthened with Carbon Fiber Reinforced Polymer Sheets
This paper presents outcomes of extensive research conducted to study the behavior of reinforced concrete (RC) beams strengthened with CFRP sheets and subjected to shear and flexural loading. A 3-dimensional Finite Element (FE) modelling was carried out using ABAQUS software program to simulate the flexural and shearing behavior of a number of RC beams strengthen with CFRP. Moreover, the results of the numerical simulation were compared with actual results of experimental physical modelling of RC beams subjected to the same loading conditions for validation purpose. Appreciable number of sets of control RC beams and CFRP strengthened RC beams for flexural and shear were investigated. All beams were rectangular in cross section. To accurately describe the behavior of these tested RC beams, different material constitutive models were used in the simulation. Concrete damaged plasticity model was used to model concrete; a linear elastic perfectly plastic model was used to model both reinforcing steel and stirrups, while a linear elastic isotropic model was used to simulate the behavior of CFRP material. Moreover, the interface between concrete and CFRP material was accounted for and was simulated using a tie perfect bond model while steel reinforcement is bonded with concrete as an embedded element in ABAQUS. A careful comparison between the results of the experimental tests and those of the numerical simulation showed that the proposed FE model is able to describe the behavior of reinforced concrete beams strengthened with CFRP in terms of crack pattern and load deflection curves to an appreciable level of accuracy. Generally, the results demonstrate that numerical approach can be used to deeply investigate the behavior of RC beams strengthened with CFRP sheets. It was also concluded that the numerical approach was able to capture significant aspects of structural behavior of the tested beams such as strain distribution in CFRP, which is often not easily captured experimentally or analytically.
An Exploratory Study of Women’s Use of Public Spaces in Greater Khartoum, Sudan. Case Study of Al-Thawra Hara 72, Omdurman
This study explores how women’s use of public spaces in Greater Khartoum is restrained by societal norms and violence imposed upon them. Furthermore, women suffer from various forms of harassment that make their journeys to work a horrendous daily experience. The study is based on fieldwork conducted in Al-Thawra Hara 72, in which women’s views were gleaned through a questionnaire, focused group discussions; in addition to observations and safety audits in the neighborhood. It was found that women’s use of public spaces is very limited and is restricted to passive activities conducted in conjunction with their children. They tend to avoid going out alone or strolling in public spaces to evade violence and harassment. The paper concludes that public spaces lack facilities that could make women’s use of them a gratifying experience. Neighborhood planning and urban design measures are proposed to foster more women’s use of public spaces.
المفاهيم المنهجية للبحت العلمي في مجال العمارة والتخطيط
Scientific research is a systematic faculty of human mind, oriented to solve a livable problem, or to explain a phenomenon, in order to enable scientific reasoning to derive solutions to the problem, or to explain correlations and causality of the phenomenon. Methodology, therein, provides the necessary logical consequence of deploying adequate and relevant processes. Deductive method, emanating from positivism, hegemonies the scientific sphere till Einstein proofed the insufficiency of empiricism to cope with the contemporary advance of science.The traditional logic of science is proved to deter the prevailing creative and innovative trends. This paper tends to scrutinize the ramifications of this complicated situation on the field of architecture and planning, aiming to highlight the dilemma facing the research methodology within the field, in a way to grope the directions of the expected paradigm shift. The criticisms casted to conventional methods of research have negatively affected that of the architecture and planning field, which suffers an ultimate inconsistency, since the field is composed of three, paradoxically, heterogeneous scientific components of: pure science, social science and art. The analysis of the paper tends to prove validity of the hypothetical deduction methodology, originated from rational criticism, to formulate the theoretical background to the new paradigm. It recommends the critical analysis method as atabula rasafor synthesizingand evaluating urban issues, while urban context and urban scape are called to circumscribe research on phenomena to their socioeconomic and sociospatial context.Urban scape is moreover utilized as a tool for analysis and evaluation
Performance of Natural Unbound Material Blended with Wadi Sand under Dynamic Loading
This paper investigates the effects of adding natural wadi sand to a typical unbound subbase material from Alsilait area in Khartoum. Four trials blends were prepared.Only two of the blends satisfied the (TRL, GB3) gradation and strength requirements of the unbound base course material. The strength, the stiffness and deformations characteristics were evaluated for the blends, using the CBR, resilient modulus (MR) and permanent deformation (PD) tests. Pavement physical models were constructed using the studied samples in the resilient modulus mould. The physical model comprises subgrade, sub-base, base course, and asphalt layer. The only variable in the physical model testing was the type of base course material. The model was subjected to dynamic loading typical to PD test conditions. The tests results have shown that the blends satisfying the GB3 base requirements measured the smallest values of permanent deformations. Minor differences were found for the PD values this also applies to the physical model tests. The study has shown that the large differences in CBR values did not result in large differences in permanent deformation and stiffness (MR) values.
Women usually find it difficult to integrate into the Construction Industry (CI); and many leave without achieving their goals and/or utilizing their true potentials. “The Leaky Pipe Syndrome” through which women opt out of CI at different stages of their career is a common scenario around the world. Moreover, a “Glass Wall”, traditional horizontal employment segregation, still persists in Sudanese CI coupled with a “Glass Ceiling Phenomena” which describes a vertical segregation limiting women chances in reaching senior decision-making positions. A previous study by the author highlighted the existence of these phenomena in the Sudanese CI. As part of a 3-year (2010-2012) research project on women participation in Sudanese CI, two extensive surveys were conducted to examine the current situation of women in CI in Khartoum. The surveys interviewed female employees and their employers in consultancy, contracting, services, material suppliers and entrepreneurs. It investigated aspects dealing with status quo, training, barriers, discrimination, social image and future outlook for the role of women in Sudanese CI. Through in depth analysis of collected data; this paper investigates the underlying factors, their manifestation in the workplace and the way forward towards a more active role for women in Sudanese CI. The research analyses similar literature and attempts to bring a comparative multidisciplinary, social, cultural and psychological perspective to the problem. The results highlighted certain barriers and constraints facing women in CI. Job retention of CI jobs was found to be particularly problematic for women affecting their professional career prospects. Their progress in the first 5-10 years in the job was found to be more variable than men and their move from junior to middle positions is particularly difficult. However, the results also indicated a positive cultural change towards women employment in general and in CI in particular.
An Approach to Community Participation Evaluation Framework
Evaluating a community participation exercise has been in the frontline of challenges faced by planners, policy-makers and academicians. In this article, a theory-driven approach to Community Participation evaluation framework/ mechanism is presented and outlined. Counting on that our theories determine what we measure, the methodology underpinning this article depends on critical analysis and evaluation of how community participation is being evaluated in 1) traditional Community Participation literature and practices; 2) Third World oriented Community Participation literature and; 3) contemporary Community Participation literature and practices. The developed framework focuses more on the procedural aspects of participation, stranding to its objectives. This article concluded by outlining a five-components framework through which Community Participation can be evaluated and measured. It is also concluded by arguing that; the approach presented can work nicely in both developed and developing world.
The Microstructure and Dispersive Characteristics of a River Nile Terrace Deposit from Northern Sudan
The microstructure of low plastic highly dispersive sandy silty clay (CL) deposit obtained from the terraces of the River Nile in Northern Sudan was studied using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) in relation to its dispersive characteristics. The study showed that the silt size of the CL is mostly aggregates of clay particles cemented by organic matter and iron oxide bonds. Kneading experiments have shown that these aggregates are unstable and could be broken by kneading and compaction. Pinhole tests on specimens prepared at wide ranges of density and water content and kept for different curing times (hours to one year) have shown that neither water content, density and curing times have pronounced effect on the dispersivity and erosion characteristics of the tested soil.
Comparative analysis on the thermal performance of selected building materials and technologies for housing in the sudan
In search for adequate and affordable housing based on appropriate local building materials and technologies, the National Fund for Housing and Rehabilitation (NFHR) has invited research institutes, professional associations and practitioners to give their suggestions and recommendations in this regard. Demonstration models were developed to show the appropriateness of some technologies and materials and the extent of its affordability. The purpose of this study is to carry out a comparative analysis between some of these different technologies in terms of economical and environmental contexts using Ecotect software. According to the analysis results, selected materials for walling and roofing are ranked based on their performance in terms of annual energy required, passive comfort, heat gains, and passive breakdown of heat gains and losses.
Codes of Practice for Geotechnical Engineering: Site Investigations ( SI ): Review Paper
This paper presents a review of some national and regional codes of practice in the area of Geotechnical engineering site investigation (SI). The goal is to identify some significant issues relevant to professional practice in Sudan and to highlight how they were approached and dealt with in different codes. The scope of the SI comprises the number of points to be investigated. these may be test pits, boreholes, field soundings, geophysical soundings. The extent of the SI is generally described by the depth of boreholes and /or types of field soundings. The scope and extent of SI are strongly related to the types of structures and loadings as well as to the geotechnical character of the site. The final result of the SI is presented in a geotechnical report, including field work, laboratory work and recommendations for design and construction. The report must be prepared by an experienced Geotechnical Engineer. The fact that SI is usually carried out in the very early stages of the project, when even the project funding may not have been fully secured, tends to create a situation where costs available for SI may be restricted. It is widely believed that SI is a very significant component of any civil engineering project. While the cost of the SI is a minor component, it is of major importance to project risk management and will positively affect total costs. It is recommended that a Sudanese Code of Practice for Geotechnical Engineering be adopted to regulate and upgrade the professional practice in this area. This activity should be carried out under the auspices of the national Standards organization. The Sudanese Society of Soil Mechanics and Geotechnical Engineering can be instrumental in these activities.
Bearing Capacity Parameters for Pipe Piles in Stiff to Hard Highly Plastic Clays
The design of steel pipe piles in clay soils is faced with insufficient information regarding the parameters used for estimation of their static ultimate load capacity, namely the adhesion factor and plug length.This paper gives guides for the selection of the mentioned parameters. Direct shear and adhesion tests were performed. The soil tested is highly plastic silty clay statically compacted in the shear box at constant dry density and varying water content covering dry and wet of optimum water content. The adhesion factorwas computed for each test condition. An average value of 0.48 was found for the interface resistance when the water content is lower than the plastic limit. The factor was found to increase with increase in water content for water content higher than the plastic limit. The Plug length data was generated from a construction site in Melut Basin in Southern Sudanwhere steel pipe piles of different sizes were driven in very stiff to hard silty clay to about the same length and driving records were recorded with extra data regarding plug lengths. Geotechnical investigation preceded the construction activities. The plug data was analyzed for the effects of pile diameter and soil conditions on the plug length. Plug length to diameter ratio ranged between 3.8 and 8.0. Plug length increased linearly with increasing pile diameter and an excellent linear relationship was obtained between the average plug length for each diameter and pile diameter. Piles with small diameter gave lower resistance to penetration compared with those with larger diameters.
Characterization and evaluation of sudanese fly ash as partial replacement for cement in concrete mixes
The main objectives of this paperare to characterize the physical and chemical properties of the locally produced fly ash, to study its suitability to be utilized in concretemixes and to determine the degree of its pozzolanicity .Physical and chemical properties of fly ash were tested according to the standards of the American Society of Testing and Materials (ASTM C311-02). Fly ash was tested for density, fineness, moisture, Loss on Ignition (LOI), chemical composition, X-ray Fluorescence test (XRF), X-ray Diffraction test (XRD) and strength test. The results were then compared with the ASTM C618-03. It was found that the locally produced fly ash contains high level of silica, hence it can be classified, based on its chemical composition, as class F fly ash; this may be probably due to the addition of sand applied in the combustion chamber. The XRD showed that it contained crystalline form of silica which is not good for the use in concrete. On the other hand, the strength test proved that there was a degree of strength and pozzolanicity obtained. The strength activity index of 28-day was found 70%.This may be due to presence of amorphous silica within the crystalline one.
The paper handles the topic of Engineering Arbitration in Sudan as one of the mechanisms of dispute resolution in engineering contracts, by mentioning parts of the international experience embodied in the FIDIC forms of engineering contracts along with the developments in Sudanese laws associated with arbitration. The paper then summaries one of the major arbitration cases in Sudan; namely the Social Insurance Towers in Khartoum as an example. Typical reasons that lead to construction disputes, both from international experiences and Sudanese practice, are listed. Having quoted the main constraints facing engineering arbitration in Sudan, the paper concludes by giving some pertinent recommendations to enhance and advance this effective mechanism of resolving engineering disputes.
تأثير إدخال بيانات الحرارة في مراحل مشروعات المباني على سمك العازل الحراري للجدران والأ سطح
This research draws the attention of structural designers and architects to the importance of employing the environmental data in all the construction stages of buildings. The research focuses on the introduction of the solar radiation values that are received by the buildings during daytime for selecting building construction material of suitable thermal specifcations, as well as design of thermal insulation thickness for the building walls and roof. The research assumes the walls and roof are the media of heat exchange between the internal space and the climate, excluding the ﬂoors. The main heat transfer equation is used for the production of values of thermal conductivity at the level of the building, not the region. The research minded the fnancial situation of the owners and assumes three thermal levels for a building in the study area (Khartoum State).
A Study on Geotechnical Properties of Weak Rocks in Sudan
Weak rocks are available in different areas in Sudan. These include sandstone, mudstone, siltstone usually referred to as Nubian Formations (N.F.). Clastic limestones are present in other areas of Sudan. Organic limestones in the form of coralline deposits are present in eastern Sudan, mainly on the Red Sea coast. Weak rocks constitute an important geological feature on which the foundations of most of the important structures are resting. The sandstone is also used as a primary building material or as a facing stone over other construction. The geotechnical properties of these formations were investigated by different insitu and laboratory testing methods. This paper summarizes the origin, distribution of Nubian formation and limestone. The paper also presents most of available data on the geotechnical properties of these formations. It is concluded that the Nubian formation and limestone coral deposit are weak rocks with poor quality of core samples; hence feld testing may give better geocharacterization result for such deposit.
Numerical Analysis of Failure Mode of Micropile in Cohesive Soil
In this paper, fnite element was used to study the behavior of micropile. The model was developed using PLAXIS 3D foundation program. Micropiles are tested by the static axial load testing of individual piles. In the FE-analysis the pile is assumed to be linear elastic and for the subsoil is assumed as Mohr-Coulomb model. The model was developed to simulate the micropiles type A where the grouting is applied by gravity. This modeliscompared with the results of the pile load test. A good agreement was obtained with the experimental results. Finally the failure pattern was investigated.
تأثير التخطيط الزمني والتدفق النقدي والعنصر البشري على تاخير تنفيذ مشروعات التشييد بولاية الخرطوم
This study was carried out in Khartoum State-Sudan during 2012-2014. The data was collected by questionnaires from the engineers working in the contracting companies. The collected data was analyzed by the statistical descriptive analysis using SPSS20 program. The main suggestions of this study for the delay in executing the engineering projects was due to (1) weakness of the contracting companies in using the engineering planning and the time schedule of the different activities, (2) low budget and irregular cash ﬂow through the life time of the projects and (3) use of unqualifed workmanship for the different activities. The results of this study showed the reality of these suggestions for the delay in executing the projects.
The Effect of Non-Orthogonal Forms on Energy Consumption in Tall Office BuildIngs
This paper focuses on the relation between the building form and energy performance in tall ofﬁce buildings. It deals with one common generic ar-chitectural form of contemporary designs and its derivations. The LT (Light and Thermal) method, developed in UK, was used to estimate expected en-ergy consumption after adjusting its assumptions to suit Khartoum’s climatic conditions and non-orthogonal forms. The ﬁndings of this study can be quite useful for architects at early stages of the design process (sketch and pre-liminary design) when no detailed information is available yet for advanced simulation and energy performance assessment techniques. The ﬁndings compare calculated energy consumption of ﬁve selected forms: box, twisted box, tapered box, bent box and tapered twisted box. The conclusions suggest that up to one-third of the variations in energy consumption could be at-tributed to changes in basic forms at early design stages. Self-shading forms with controlled glazing ratio perform noticeably better than other forms.
Characterization and Improvement of Natural and Blended un-bound Gravels From Khartoum State for Use as Base Course Material
This paper presents the outcome of a comprehensive testing program aimed at studying the strength, stiffness and deformation characteristics of three selected natural unbound materials in their natural state and when blended with Wadi sand or crushed stone with different size grades to satisfy base course specifcations. A graded crushed stone sample was prepared as reference material. The natural materials C1, M2 and F3 were obtained from open quarries to represent coarse, medium and fne gradations, respectively. The materials were also stabilized with cement. Only 1% cement by weight of dry material rendered the three unbound gravels to behave as rigid materials. The California Bearing Ratio (CBR), resilient modulus (MR) and permanent deformation (PD) tests were performed on the natural, blended and stabilized samples for determination of their strength, stiffness and deformation characteristics. Initial assessment of the improvement methods has shown that the strength (CBR) of the three materials, blended with Wadi sand, signifcantly improved to satisfy or nearly satisfy the GB3 requirement. Blending with crushed stone improved the gradation and caused large increase in strength (CBR) of the three materials. Cement stabilization of the three materials using 1% cement by weight of dry material rendered them to become hard material with CBR exceeding 100%. Further study of the stiffness and deformation characteristics of the studied materials has shown that blending with crushed rock gave better results in terms of increase in stiffness compared to Wadi sand when coarse gravel size material was added. It was enhanced by the improvement of gradation and interlocking caused by the shape of the coarse crushed stone particles. The crushed stone mix measured MR values exceeding 250 kPa indicating very stiff mix of superior quality when compared to the naturally occurring unbound materials and their corresponding blended products. Cement stabilization resulted in a very rigid material with MR values twice those for the pure crushed stone sample. The graded pure crushed stone sample showed very high resistance to permanent deformation when compared to the natural or blended materials. Blending a material with graded crushed stone gave lower PD values compared to blending the same material with Wadi sand. This investigation has also shown that blending with sand and crushed rock could result in high increase in the strength of unbound material as demonstrated by CBR values, but would not necessarily result in comparable increase in rigidity or in resistance to permanent deformation
Indicators for measuring Performance of Municipal Solid Waste Management in Khartoum State
Population and urbanization growth caused an increase in the amount of solid waste generated. The 7- cleaning projects responsible for the collection and transport of Solid Waste (SW) for Khartoum State are currently unable to perform their duties to the level expected with the result that the city is unclean and there is considerable impact on the environment and health of the citizens. There is a need to quantify these general observations. This is done by the use of Key Performance Indicators (KPIs). This paper aims to identify a set of KPIs for measuring the performance of Solid Waste Management (SWM) system at the collection and transport level. The study targeted the 7-cleaning projects -in particular, the operation department responsible for collection and transport of SW for each cleaning project together with the operation department at the Supervisory Authority of Cleaning Khartoum (SACKH) which supervises their work. List of 28 potential performance indicators have been identifed through the literature review. A survey questionnaire was conducted on a randomly selected sample of the operation departments . The statistical analysis of the collected responses was provided in 11 signifcant KPIs. It is hoped that the results of this study will become the frst step in developing Integrated KPIs for enhancing the performance of SWM of Khartoum state- the capital of Sudan.
Building and Road Research Institute University of Khartoum
Comparison between Radiance Daylight Simulation Software Results andMeasured on-Site Data
The paper focuses on comparing the popular daylight simulation softwareresults against the measured on-site data; it investigates softwareaccuracy and its limitations when used to calculate the daylight illuminance in clear sky conditions. The objective of the study is to examine the existence of any discrepancy and identify any systematic trend between actual and predicted results. Petrodar and NTC, both high-rise office buildings in Khartoum, were selected as case studies for the validation purposes. The study concluded that the diffuse daylight was simulated more accurately than the direct component. The variation between the measured values and simulated ones occurs at the points facing direct sunlight, and mostly when the sun comes at a low angle, this variation reached twice the measured in four cases. The study highlights the need for more refinement of the software when simulating direct component of daylight in clear sky conditions.
Characterization and Evaluation of Giad Arc Furnace Slag as Partial Replacement for Cement in Mortar Mixes
The main objective of the research presented in this paper is to conduct a physical and chemical characterization of the locally produced Electric Arc Furnace Slag (EAFS) that produced by Giad Company for Industries, and to determine the degree of its Pozzolanicity. Also the aim of the study is to explore the possibility and feasibility of using this industrial waste as a cement replacement in mortar mixes. Different percentages of cement replacement with the slag had been studied (namely 20%, 30%, 40% and 50% with the slag had been studied respectively). Chemical and physical properties of the slag were studied in accordance to the international standards (ASTM and BS) specially the American Society for Testing and Materials (ASTM C311). Chemical analysis showed that locally produced steel slag contains high amount of iron due to purification process in steel manufacturing comparing the results with standard (ACI 233). Also testing of raw materials such as fineness, loss on ignition and X-ray diffraction test (XRD) were carried out. After that the required tests on cement mortar were carried out namely; consistency test, initial and final setting times and strength test according to the standard. XRD analysis results showed presence of both crystalline and non-crystalline silica (Amorphous) which indicated good pozzolanicity of the slag. A degree of pozzolanicity of 83.4% at 28 days indicates a good quality electric arc furnace slag and a promising pozzolanic supplementary material in concrete. Compressive strength test of mortar samples in 2, 7, 14 and 28 days with different percentages of electric arc furnace slag (0%), 20%, 30%, 40% and 50% had been conducted. Finally, the study proved the efficiency and feasibility of using one of the industrial wastes as a cement replacement in concrete industry in Sudan
Numerical Simulations for Analysis of Face Stability of Tunnelling
The aim of this paper is to evaluate numerical procedures that are used for analysis of face stability of a tunnelling. Two-dimensional (2D) and threedimensional (3D) Finite Element (FE) modelling of the Second Heinenoord Tunnel in Netherlands were done by using PLAXIS programs. The models were simulated the tunnel boring machine (TBM) with shell element and the slurry pressure with applied face pressure that measured in the site from the literature. Two methods were used to determine the situation of face failure. The first method was done by reducing the applied face pressure until the failure of the face was occurred, so the minimum required face pressure was determined. The second one was done by reducing the shear strength of the soil until the face failure, so the safety factor was determined. Both methods were applied for 2D and 3D FE-modelling. The results were presented and discussed. Also, the results of the minimum required support pressure were compared to the result of the centrifugal test model for the Second Heinenoord Tunnel found in literature. It was found that, the reducing applied face pressure method is much better than the reducing shear strength method. Also, the result of 3D FE-modelling gave better prediction when comparing with the experimental result .
Experimental Study of the Bearing Capacity of Footings on Stiff Clay Overlying Very Loose Sand
Experimental model tests were carried out to study the bearing capacity of footings on stiff clay overlying very loose sand. Emphasis was given to the effects of the thickness of the clay (H) relative to the footing size (D). The clay thickness was fixed during the experiments and the foundation was represented by rigid circular steel plates of different sizes to give H/D ratios ranging from 0.6 to 2.0. The shear parameters of the two soils were measured in the laboratory at their placement conditions. The load tests were carried out to failure. The load settlement curves showed non-linear relationship. The ultimate bearing capacity decreased with increasing plate diameter. For the same plate (150mm) the bearing capacity on homogeneous stiff clay is more than twice that of the stiff clay overlying loose sand. The bearing capacity factor Nc was back-calculated from the results of the model tests. The very loose sand caused the factor to decrease to values less than 3.0 for H/D smaller than 1.0. The effective depth which is the smallest thickness of the stiff clay that does not allow the lower layer to affect bearing capacity is greater than twice the plate diameter (> 2D).
The Influence of Structures Syllabus in Architectural Education in the Integration between Architects and Structural Engineers
The integration level between architects and structural engineers in practice is perceived as very low in terms of integration to enrich the architectural value. This research aims at investigating the role of structures syllabus design and teaching methods on the integration between architects and structural engineers in both education and practice. A combination of qualitative research methods is used to investigate this issue, including questionnaires and structured interviews conducted at the Faculty of the Architecture (FoA), University of Khartoum (U of K), as a case study. The survey questions involved a combination of close-ended questions; multi-choice and ranking questions to be answered in an ordinal scale in a form of a five-point Likert-scale. The research findings suggest that the teaching methods of structures in architectural education contribute to the disintegration and lack of collaboration between architects and structural engineers in both education and practice. The study suggests that implementing architectural-based approaches in teaching structures may lead to the improved integration between architects and structural engineers.
Experimental and Finite Element (FE) Studies on the Behaviour of Horizontally Curved Composite Bridges Deck
This paper aims to study the behaviour of horizontally curved composite steel-concrete bridges deck slab and beams under static load, using experimental tests and nonlinear finite element analysis. Two different specimens were examined in the structure laboratory, one of them was horizontally curved composite deck slab and steel girders with full interaction between the concrete deck and the steel girders, while the other with partial interaction. Each specimen has three curved I-girders acted parallel connected with X shape cross frames. Linear Variable Differential Transducers (LVDT) and strain gauges were used at critical points to measure deflections and strain respectively. Three dimensional finite element (FE) models with 137119 elements were built and analysed using ANSYS software version 14. Models dimensions were 1/10 in both length and radius of curvature of the Federal Highway Administration (FHWA) full scale model. Numerical results have been compared with the experimental test results. Maximum values and distribution of both stresses and strains at top flanges, bottom flanges and the web tension zone for numerical modelling results, showed close agreement with the experimental tests results in both full and partial interaction models. Also, similar failure modes were encountered from both numerical modelling and experimental tests. Maximum deflection values obtained from numerical modelling were slightly below the experimental values and this was attributed to the stiffer numerical model. Further, mesh refinement could have increase accuracy of numerical predictions.
Quality Assurance and Control of the Largest and Longest Continuous Concrete Pour in Sudan
This paper aims to document the largest and longest continuous concrete pour in hot weather in Sudan which had been carried during the casting of the raft foundation of the National Club Project in Khartoum. The paper describes the planning and logistics management taken before, during, and after the pour in addition to the adopted quality control and quality assurance processes. Moreover,the paper assesses the quality of the produced concrete in 7 and 28 days age using different codes. The results shows that the concrete strength is satisfied the project requirements. Also, the paper present the spatial distribution of concrete strength over the raft foundation.