www.sudacon.net for construction news in Sudan

www.sudacon.net is a website created by Dr. Amged O. Abdelatif, a Research Fellow at the University of Nottingham, Civil Engineering Department. The website concerns the latest news in the construction sector in Sudan. It provides an update of the labor and material prices, jobs, tenders/bids, and other related topic. The website also represents a platform for the FixKhartoum project. This project is acting as a tool to report issues in roads and streets such as pothole problems, lighting problems, and leakages

Challenges Facing Building Information Modelling in Construction Industry in Sudan

Building Information Modelling (BIM) is a valuable and promising approach in Architecture, Engineering and Construction (AEC) industry, which is gradually gaining acceptance by owners, architects, engineers, and contractors as an innovative process of generating and managing building data during its lifecycle. This paper aims to mark the main challenges that are faced by the adoption of BIM and the current BIM maturity level in Sudan. The most challenging issue was found to be the absence of clients demand to implement BIM in their projects. According to this study, the maturity level in AEC in Sudan was found to be Level 1

Accelerated Corrosion Tests on Lapped Spliced Joints in Concrete

This paper presents a new test setup of experiments to investigate corrosion at lapped spliced joints using accelerated corrosion test. The experiments were carried out on two set of samples: cylinders and beam blocks. Corrosion current readings were recorded with time and samples monitored for cracking pattern during the test. The results show that the cracks appearance and severity depend mainly on the cover diameter ratio. Also, the paper shows how the corrosion cracks propagate at lapped splice joints in concrete. The comparison of the results with previous literature was satisfactory

Modeling the re-anchoring of a ruptured tendon in bonded post-tensioned concrete

: In this study, a theoretical model is deve loped to simulate the re-anchorage of a ruptured bonded post-tensioning tendon. This includes estimating the re-anchorage length and stress distribution over the tendon. The model accounts for equilibrium and compatibility conditions at the steel-grout, grout-duct and duct-concrete interfaces as well as the effect of axial stresses in the strand and its confining materials, i.e. grout, duct and concrete. Formulation of the model is based on the elastic theory of thick-wall cylinders and the Coulomb friction model. The model has been validated against an axi-symmetrical Finite Element (FE) model, the UK Highway Agency’s BA51/95 model and previous experimental data. The models had been compared with the UK Highway Agency’s BA51/95 model and previous experimental data

Re-anchorage of a ruptured tendon in bonded post-tensioned concrete beams: model validation

Many post-tensioned concrete bridges have been reported to have ruptured tendons due to corrosion [1] and the assessment of their residual structural capacity has to account for the possibility of re-anchorage of failed tendons. This paper presents an experimental programme to validate a numerical model developed by the authors for the re-anchorage of a ruptured tendon in post-tensioned concrete [2]. The experimental programme considered 33 post-tensioned concrete prisms, in which the rupture of tendon was simulated by releasing the tendon at one end. The full field displacement at concrete surface after release was measured using 3D Electronic Speckle Pattern Interferometry (ESPI). A wide range of parameters: tendon diameter, duct material, grout strength, concrete strength and shear reinforcement were investigated to validate the proposed model, which is found to be suitable for use in assessing post-tensioned concrete bridges with damaged tendons

Modeling the re-anchoring of a ruptured tendon in bonded post-tensioned concrete

: In this study, a theoretical model is deve loped to simulate the re-anchorage of a ruptured bonded post-tensioning tendon. This includes estimating the re-anchorage length and stress distribution over the tendon. The model accounts for equilibrium and compatibility conditions at the steel-grout, grout-duct and duct-concrete interfaces as well as the effect of axial stresses in the strand and its confining materials, i.e. grout, duct and concrete. Formulation of the model is based on the elastic theory of thick-wall cylinders and the Coulomb friction model. The model has been validated against an axi-symmetrical Finite Element (FE) model, the UK Highway Agency’s BA51/95 model and previous experimental data. The models had been compared with the UK Highway Agency’s BA51/95 model and previous experimental data

Development of coupled centrifuge-numerical modelling: investigation of global tunnel-building interaction

There is an increasing demand for underground space in urban areas for infrastructure development. This has resulted in tunnel construction taking place in close proximity to buried infrastructure and building foundations. Various studies have considered the effect of tunnel construction on buildings; however the global tunnel-ground building interaction problem is still not well understood. This is due partially to the fact that the available modelling tools do not accurately replicate the global behaviour of soil-structure domains. This research aims to enhance physical modelling capabilities by coupling centrifuge and numerical techniques. The research focuses on tunnelling beneath buildings which are founded on piled foundations. In this paper, the proposed method and the developed equipment are presented. The expected outcomes of this research will provide a better understanding of complex tunnel-ground-building interactions which will help to improve the design approach of tunnels beneath buildings

Development of coupled centrifuge-numerical modelling: investigation of global tunnel-building interaction

There is an increasing demand for underground space in urban areas for infrastructure development. This has resulted in tunnel construction taking place in close proximity to buried infrastructure and building foundations. Various studies have considered the effect of tunnel construction on buildings; however the global tunnel-ground building interaction problem is still not well understood. This is due partially to the fact that the available modelling tools do not accurately replicate the global behaviour of soil-structure domains. This research aims to enhance physical modelling capabilities by coupling centrifuge and numerical techniques. The research focuses on tunnelling beneath buildings which are founded on piled foundations. In this paper, the proposed method and the developed equipment are presented. The expected outcomes of this research will provide a better understanding of complex tunnel-ground-building interactions which will help to improve the design approach of tunnels beneath buildings

Production of Self-healing Concrete using Gum Arabic for Immobilizing of Bacterial Spores on Sand

This paper studies the feasibility of producing self-healing concrete by immobilization of bacteria on the sand. In this study, the Gum Arabic (Acacia Senegal) was used to immobilize bacterial spores and its nutrient (Calcium lactate) on sand surface as a novel technique. Due to its availability and environment-friendly character, Bacillus subtilis bacteria have been selected and prepared. To achieve the aim of this study, three concrete mixes were made with 10%, 5%, and 2.5% of gum-capsulated sand with bacteria. The ability of self-healing of cracks was monitored using stereomicroscope and digital image camera. The experiments have shown that the proposed technique is efficient in healing of cracks without impairing the prisms' strength for mixes with 2.5% and 5% of gum-capsulated sand with bacteria. The results give a proof-of-concept to use Gum Arabic as an adhesion to immoblize the bacteria and its nutrient on sand to produce self-healing concrete

Modeling Short-Term Deflection of Reinforced Concrete Slabs using the Layered Approach

This paper examines the short-term deflection of reinforced concrete slabs taking the tension-stiffening phenomenon into account. The main goal of this study is to develop a model that predicts the deflection of one-way slabs made of reinforced concrete. The model takes into account concrete contribution in carrying tension between cracks thoroughly considering the stress-strain relationship material model. The model has been developed using MATLAB Program incorporating a numerical technique known as the layered approach. The developed layered approach model was validated using experimental deflection results reported in a previous study. Based on the experimental validation, the model showed its tendency in predicting the real-case deflection of one-way concrete reinforced slabs. It was concluded that different types of tension stiffening models can be added to the program to model deflection and crack propagation