Abstract— Extreme weather events due to global warming become more frequent and intense in Egypt. Recently, some interior parts of Egypt saw torrential heavy rainfall and even snow for the first time in nearly half a century. Global warming consequences threaten Egypt's densely populated coastal strip and Nile Delta, and could have grave consequences for the country's economy, agriculture and industry. A rise of only 30cm to the sea level over the next 15 years would flood 200 square kilometers and displace 500,000 people, effectively ending 70,000 agricultural jobs. Planners and Decision makers are required to think about new scenarios and strategies which are raised as challenge in front of the recent climate changes in Egypt and related impacts. This paper describes recent climate changes impact in Egypt, its future impacts and tries to define defensive actions against the expected global warming crisis on Egypt.

Concrete reinforced with short steel fibers is associated with its significant ability to control cracking and enhances its ductility and tensile properties. For this reason, steel fiber reinforced concrete (SFRC) has been widely used in RC structures, where tensile cracks very often occur. In the current work, an experimental program was developed to experience the flexural behavior of the two-layered concrete beams. The tensile zone of the investigated RC beams is made of steel fiber reinforced concrete (SFRC), while the compression zone was developed from normal strength concrete (NSC). Eight RC beams specimens of size 120*300*2300 mm were tested under one-point static loading to study the influence of different fiber ratios and the height of SFRC layer on flexural behavior of concrete. Crack width, crack propagation, deflection, steel strain, and concrete strain were measured and presented in this investigation. The test results indicated that, intensive improvement on overall flexural performance with respect to the corresponding non-layered control beams. Adding of steel fibers in the lower layer of concrete beams (tensile zone) increases the first cracking and ultimate loads, stiffness and ductility of the concrete beams.

An experimental study on the strength and deformation of concrete filled square box stub-columns is presented. Twelve specimens of concrete filled composite columns were tested under centric and eccentric static loading up to failure. Another steel hollow square box specimen was tested under centric static loading up to failure. Vertical stiffeners were used as shear connectors between concrete and steel columns. Seven specimens were filled with normal strength concrete (30 MPa), while five specimens were filled with high strength concrete (65 to 90 MPa). The effect of strength of concrete, composite action between steel and concrete, and eccentricity of the load are considered in this study. Comparison between the experimental strength of the tested specimens and their predicated strength that calculated by several formulas was also presented. Considerable and beneficial recommendations to such composite columns were also given.

Experimental tests were carried out to study the effect of using combining steel and polypropylene fibers on cracking resistance of R.C. elements under both static and dynamic loading. The tested R.C. elements were containing of steel, polypropylene and combination of both steel and polypropylene fibers, using dosages as 1.0 %, (by volume).The tested R.C. elements were reinforced with constant amount of steel bars and constant cross-section. They tested under four point both static and dynamic loading. The mid-span deflections, crack width, number of cracks, first crack load, and ultimate load capacity were recorded as well as cracks propagation were observed. The experimental results show that the R.C. elements containing of combining steel and polypropylene fibers are enhanced improvements in the cracking resistance and their characteristics as will as their serviceability when compared with using individual fibers.

Damage assessments after past earthquakes have frequently revealed that plan configuration irregular buildings have more severe damage due to excessive torsional responses and stress concentration than regular buildings. The plan configuration irregularities introduce major challenges in the seismic design of buildings. One such form of irregularity is the presence of re-entrant corners in the L-shaped buildings that causes stress concentration due to sudden changes in stiffness and torsional response amplification; hence causes early collapse. A constructive research into re-entrant corner and torsional irregularity problems is essentially needed greater than ever. Therefore, the focus of this study is to investigate structural seismic response demands for the class of L-shaped buildings through evaluating the plan configuration irregularity of re-entrant corners and lateral–torsion coupling effects on measured seismic response demands. The measured responses include story drift, inter-story drift, story shear force, overturning moment, torsion moment at the base and over building height, and torsional irregularity ratio. Three dimensional finite element model for nine stories symmetric buildings as reference model is developed. In addition, six L-shaped building models are formulated with gradual reduction in the plan of the reference building model. The results prove that building models with high irregularity are more vulnerable due to the stress concentration and lateral torsional coupling behavior than that with regular buildings. In addition, the related lateral shear forces in vertical resisting elements located on the periphery of the L-shaped buildings could be significantly increased in comparison with the corresponding values for a symmetric building.

Damage assessments after past earthquakes have frequently revealed that plan configuration irregular buildings have more severe damage due to excessive torsional responses and stress concentration than regular buildings. The plan configuration irregularities introduce major challenges in the seismic design of buildings. One such form of irregularity is the presence of re-entrant corners in the L-shaped buildings that causes stress concentration due to sudden changes in stiffness and torsional response amplification; hence causes early collapse. A constructive research into re-entrant corner and torsional irregularity problems is essentially needed greater than ever. Therefore, the focus of this study is to investigate structural seismic response demands for the class of L-shaped buildings through evaluating the plan configuration irregularity of re-entrant corners and lateral–torsion coupling effects on measured seismic response demands. The measured responses include story drift, inter-story drift, story shear force, overturning moment, torsion moment at the base and over building height, and torsional irregularity ratio. Three dimensional finite element model for nine stories symmetric buildings as reference model is developed. In addition, six L-shaped building models are formulated with gradual reduction in the plan of the reference building model. The results prove that building models with high irregularity are more vulnerable due to the stress concentration and lateral torsional coupling behavior than that with regular buildings. In addition, the related lateral shear forces in vertical resisting elements located on the periphery of the L-shaped buildings could be significantly increased in comparison with the corresponding values for a symmetric building.

Damage assessments after past earthquakes have frequently revealed that plan configuration irregular buildings have more severe damage due to excessive torsional responses and stress concentration than regular buildings. The plan configuration irregularities introduce major challenges in the seismic design of buildings. One such form of irregularity is the presence of re-entrant corners in the L-shaped buildings that causes stress concentration due to sudden changes in stiffness and torsional response amplification; hence causes early collapse. A constructive research into re-entrant corner and torsional irregularity problems is essentially needed greater than ever. Therefore, the focus of this study is to investigate structural seismic response demands for the class of L-shaped buildings through evaluating the plan configuration irregularity of re-entrant corners and lateral–torsion coupling effects on measured seismic response demands. The measured responses include story drift, inter-story drift, story shear force, overturning moment, torsion moment at the base and over building height, and torsional irregularity ratio. Three dimensional finite element model for nine stories symmetric buildings as reference model is developed. In addition, six L-shaped building models are formulated with gradual reduction in the plan of the reference building model. The results prove that building models with high irregularity are more vulnerable due to the stress concentration and lateral torsional coupling behavior than that with regular buildings. In addition, the related lateral shear forces in vertical resisting elements located on the periphery of the L-shaped buildings could be significantly increased in comparison with the corresponding values for a symmetric building.

Recent earthquakes have demonstrated that buildings with irregular configuration are more vulnerable to earthquake damage. Moreover, the configuration irregularities introduce major challenges in the seismic design of building structures. One such form of irregularity is the presence of re-entrant corners and torsional irregularity that causes stress concentration due to sudden changes in stiffness and torsion amplification in buildings. Constructive research into re-entrant corner and torsion-irregular buildings is therefore needed to evaluate the seismic response demands for reducing the potential damage. The aim of the study reported in this paper is to grasp the seismic performance of L-shaped irregular buildings with moment-resisting frames through an evaluation of the irregularity effects on measured seismic response demands. The results for inter-storey drift, storey shear force, overturning moment, torsion–moment responses at the base and along the building height, top-floor displacement and torsional irregularity coefficient prove that buildings with irregularity are more vulnerable than those with a regular configuration resulting from stress concentration and coupled lateral–torsional behaviour.

Recent earthquakes have demonstrated that buildings with irregular configuration are more vulnerable to earthquake damage. Moreover, the configuration irregularities introduce major challenges in the seismic design of building structures. One such form of irregularity is the presence of re-entrant corners and torsional irregularity that causes stress concentration due to sudden changes in stiffness and torsion amplification in buildings. Constructive research into re-entrant corner and torsion-irregular buildings is therefore needed to evaluate the seismic response demands for reducing the potential damage. The aim of the study reported in this paper is to grasp the seismic performance of L-shaped irregular buildings with moment-resisting frames through an evaluation of the irregularity effects on measured seismic response demands. The results for inter-storey drift, storey shear force, overturning moment, torsion–moment responses at the base and along the building height, top-floor displacement and torsional irregularity coefficient prove that buildings with irregularity are more vulnerable than those with a regular configuration resulting from stress concentration and coupled lateral–torsional behaviour.

Recent earthquakes have demonstrated that buildings with irregular configuration are more vulnerable to earthquake damage. Moreover, the configuration irregularities introduce major challenges in the seismic design of building structures. One such form of irregularity is the presence of re-entrant corners and torsional irregularity that causes stress concentration due to sudden changes in stiffness and torsion amplification in buildings. Constructive research into re-entrant corner and torsion-irregular buildings is therefore needed to evaluate the seismic response demands for reducing the potential damage. The aim of the study reported in this paper is to grasp the seismic performance of L-shaped irregular buildings with moment-resisting frames through an evaluation of the irregularity effects on measured seismic response demands. The results for inter-storey drift, storey shear force, overturning moment, torsion–moment responses at the base and along the building height, top-floor displacement and torsional irregularity coefficient prove that buildings with irregularity are more vulnerable than those with a regular configuration resulting from stress concentration and coupled lateral–torsional behaviour.