Egyptian Code Research Articles

Evaluating the code approaches for estimating the seismic drifts of steel frame buildings designed under variable levels of seismicity

Two different approaches are considered by seismic codes for estimating the seismic drifts of moment resisting steel frames (MRSFs). The first approach which is adopted by the European and the Canadian codes is driven by the equal displacement rule and defines the deflection amplification factor (DAF) to be equal to the response modification factor R. The second approach which is motivated by the opinion of professionals who believe that the equal displacement rule often over-estimates displacements is employed by the ASCE 7-10 and the Egyptian seismic code, where the DAF is considered equal to a fraction of R. This study evaluates the two approaches considered for estimating the seismic drifts of MRSFs. Four MRSF buildings having 2-, 4-, 8- and 12-stories have been designed under variable levels of seismic intensity. Five lateral-stiffness scenarios are considered for each building to account for the stiffness increase due to the nonstructural components as well as the modeling approximations. The seismic drifts of the MRSFs are calculated under the effect of twenty-two pairs of far-field ground motion records by time history analysis and with using the code simplified approaches. The results obtained indicate that the current code approaches of amplifying the elastic drifts significantly overestimate the seismic drifts of buildings designed under low level of seismicity. In contrast, the ASCE 7-10 and the Egyptian code approaches of estimating the seismic drifts underestimate the maximum story drift ratios under earthquake loading for long period buildings designed under high level of seismicity.

Behavior of high-strength concrete interior slab-column connections with openings under seismic loading

Abstract Nine full-scale reinforced High-Strength Concrete (HSC) and Normal-Strength Concrete (NSC) interior slab-column connections with openings have been tested under seismic loading. The applicability of the punching shear design provisions of ACI 318-2014 building code, the Egyptian code (ECP 203-2017) and the code of the Japan Society of Civil Engineering (JSCE-2007) when applied to HSC interior slab-column connections have been examined. The main studied parameters is the concrete strength (NSC with fc‘ = 25 MPa and HSC with fc‘ = 75 MPa) and the openings location and size. A numerical model for predicting the seismic behavior of interior slab-column connections has been proposed using three dimensional finite element computer program. The results show that the punching shear strength calculated using the equations of the ACI 318-2014 are conservative for NSC and HSC specimens, while for ECP 203-2017 the calculated values are conservative for NSC specimens and just safe for HSC specimens.

Effect of Using Compressed Stabilized Earth Blocks on the Thermal comfort in Architectural Spaces

The problem of high building materials prices, using traditional building systems, consumes a great deal of energy during manufacturing or operating the facility. Accordingly, many researchers have been taken out recently to find alternatives traditional building systems and materials such as Compressed Stabilized Earth Blocks, which relates on using available natural soil compressed at high pressure, This research aims to evaluate the effect of Compressed Stabilized Earth Blocks as alternative walls for walls made from traditional blocks on thermal comfort in architectural spaces through using (Design builder) for defining energy consumption. Two types of natural soils were used (Sandy soil and Silty soil) and a partial replacement was made to the used soil types by utilizing some materials Aswan clay and Clay soil in order to improve soil performance then adding 8% cement of the total weight for stabilizing the mix. Building blocks were made of best 8 mixes in order to achieve the requirements of Egyptian Code for building by Stabilized Earth Blocks. This study is conducted on a residential sample (Social Housing sample composed of two residential units with a total area of 90 m2 for each) for comparison between building blocks made from stabilized soil and other blocks made from local brick units. Experimental results shown that the usage of building blocks, made from stabilized soil with 8% cement, helps to reduce energy consumption in order to achieve thermal comfort ranging from 5% to 25%, compared with other brick types. It also helps to reduce resources and energy consumption used in manufacturing and to decrease negative environmental impacts resulting from other building materials. Research recommendations refer to the necessity of using soil in producing building blocks in new projects under design for choosing best usage of soil and stabilize it in order to benefit from natural materials, rationalize electric power consumption in buildings

Experimental investigation of strengthening slab-column connections with CFRP fan

Abstract This paper investigates experimentally the punching shear behavior of flat slabs-column connections strengthened with CFRP (Carbon fiber reinforced polymer) string having a fan shape as a new strengthening technique. Six square slabs with middle column heads were casted monolithically at the center of the slabs. All the specimens had the same dimensions and the same reinforcement detailing. Four slabs were strengthened with CFRP fan, one strengthened with steel bolts while the reference specimen was tested without strengthening. The results showed that the proposed strengthening technique improved the punching shear capacity and enhanced the ductility of the flat slabs column connections compared with un-strengthened connections. Punching shear failure load achieved by experimental testing showed a reasonable agreement with the calculated punching failure loads based on formulas adopted by different codes: ECP (Egyptian code of practice), ACI-318 (American concrete institute) and JSCE (Japan society of civil engineers).

Analytical Behavior of High and Ultra-High Rise Structures Using Different Lateral Load Carrying Systems

A real residential building consists of 15 stories which have been built in Cairo – Egypt is studied against lateral loads, also the linear analysis repeated for the same building after increasing the number of repeated stories reaching 30, 45 and 60 stories,using two lateral load resisting systems which are outriggers and bracing systems. The ETABS 2015 program is used to analyzeall the buildings by the Egyptian, European and American codes. The most common high rise buildings in Egypt consists of 15 to30 stories, so linear analysis was conducted to the 30 stories building using Egyptian, European and American codes but in different region and soil type than what they were studied. Seismic demands were studied are the base shear force resulted fromthe seismic loads on the structure, the inter-story drift between the stories of the structure, the maximum displacement of thestructure and the weight of reinforced concrete and steel bracing in the structure. Finally, the nonlinear analysis applied to the 30stories building. It is concluded that the Egyptian code gives base shear, maximum displacement and total weight of the buildingmore than that of the European and the American codes, the buildings contain outriggers and belts system have more weight than building contain bracing system while the both have the safety requirements for the building, the total weight of the buildingincreased slightly by changing the region of the building from the seismic region to higher seismic region while the quantity of the lateral load resisting system increased extremely, finally the nonlinear analysis of the buildings give near results to the linearanalysis so the linear analysis can be dependable

Evaluating the inelastic displacement ratios of moment-resisting steel frames designed according to the Egyptian code

Seismic codes estimate the maximum displacements of building structures under the design-basis earthquakes by amplifying the elastic displacements under the reduced seismic design forces with a deflection amplification factor (DAF). The value of DAF is often estimated as ρ × R, where R is the force reduction factor and ρ is the inelastic displacement ratio that accounts for the inelastic action of the structure according to the definition presented by FEMA P695. The purpose of this study is to estimate the ρ-ratio of moment resisting steel frames (MRSFs) designed according to the Egyptian code. This is achieved by conducting a series of elastic and inelastic time-history analyses by two sets of earthquakes on four MRSFs designed according to the Egyptian code and having 2, 4, 8 and 12 stories. The earthquakes are scaled to produce maximum story drift ratios (MSDRs) of 1.0%, 1.5%, 2.0% and 2.5%. The mean values of the ρ-ratio are calculated based on the displacement responses of the investigated frames. The results obtained in this study indicate that the consideration of ρ for both the roof drift ratios (RDRs) and the MSDRs equal to 1.0 is a reasonable estimation for MRSFs designed according to the Egyptian code.

The Grounds for Setting Aside Arbitral Awards under the Egyptian Arbitration Code: Unresolved Choice of Law Issues and Unwanted Extraterritorialism

Abstract This article analyses the choice of law issues associated with setting aside an arbitral award under the Egyptian Arbitration Code (the Code), the challenges posed by applying the Code to arbitration conducted outside Egypt, and the lack of a clear criterion to define the Code’s scope of application. Choice of law issues – such as the law governing the parties’ capacity, the law governing the agreement to arbitrate and the applicable curial – are not addressed by defined choice of law rules. Under Egyptian law, there are several conflicting choices of rules. Finally, the article focuses on the Egyptian courts’ tendency to apply Egyptian law extraterritorially, either to protect Egyptian public policy or to apply Egyptian mandatory rules to determine the procedural validity of the arbitral award and the arbitration proceedings in general.

Construction Rubble, Foundry Sand and Marble Waste Powder; as Raw Materials on Concrete Bricks Production

The construction wastes is one of the environmental problem not only in Egypt but also in the whole world. The main objective of this paper to evaluated the fully replacing of natural aggregate (NA) by construction wastes (CW), full replace of natural sand (NS) by foundry sand (FS) and partially replaced of Portland cement (OPC) by marble fine waste (MFW) on the compressive strength was found out at 7, 28 days and 90 days and explained if these trials could be used in bricks manufacturing so Concrete cubes of size 150*150*150 mm were prepared in this paper with a different replacement ratio of Portland cement (PC) by marble fine waste (MFW) were 0%, 10%, 20%, 30% and 50% by weight of cement. Results show that the compressive strength by 0%,10% 20%, 30% and 50% at 7, and 28 days which the cement was replace ratio of marble fine waste (MFW) (140-141,92-91,90-86,82-80,and 73-76 kg/cm2) respectively. The compressive strength of sample 50% replacement gives compressive strength (73 – 76 kg/cm2) which consider as lowest compressive strength of these trials however it utilized maximum amount of marble dust which contributed to the elimination of the largest amount of wastes and also can be used successfully in the concrete bricks manufacturing as Egyptian standard No. 1292 and Egyptian code ECP 204 which give the compressive strength is 70 kg/cm2. The present study demostrated that, the mixture can used in brick manufacturing as shipper and green method to utilize the different waste and make new sustainability products.

Flexural analysis of RC rectangular slabs subjected to patch load

Many reinforced concrete slabs are subjected to heavy concentrated loads. Deck slabs in slab/girder bridges are subjected to wheel load distributed on contact area touches the slab surface. A large number of rectangular concrete slabs were analyzed using Finite Element (FE) analysis. The slabs were subjected to patch load applied at the center of slabs. Concentrated loads were applied on square or rectangular areas and the slabs were clamped on all four edges. The results were compared to the recommendations given by the Egyptian Code for RC slabs subjected to concentrated loads. Based on the results of comparison, suggested formulas, for load distribution in the two directions and dispersal in plan, were suggested and tested against the FE results.

Comparison of Egyptian Code 2012 with Eurocode 8-2013, IBC 2015 and UBC 1997 for seismic analysis of residential shear-walls RC buildings in Egypt

Abstract This paper presents comparative study for seismic provisions of four building codes (Egyptian Code for Loads ECL 2012, Eurocode 8-2013, IBC 2015 and UBC 1997) to the prevailing multistory residential reinforced concrete buildings comprising shear-walls (SW) and located in Cairo-Fayoum zone. Ten-story and twenty-story buildings were analyzed using the equivalent static load method (ESL) and modal response spectrum method (MRS). Simplified time approach (STA) and realistic time approach (RTA) were adopted for estimating the fundamental time period (T). The building base shear, SW moment, SW steel reinforcement, and story-drift resulted from 32 three-dimensional finite element numerical simulations (two buildings × four codes × two analysis methods × two T approaches) were compared to draw conclusions for safe design without exaggerated conservativeness. The results motivate engineering firms to stop using highly conservative UBC 1997, encourage engineers to adhere to MRS and RTA, increase the confidence level in ECL, and prompt ECL committee to provide T-formula for SW buildings.

Response modification factors of buckling-restrained braced frames designed according to the Egyptian code

Over the past two decades, buckling-restrained braces (BRBs) have become increasingly popular as a lateral resisting system because of their capability to provide energy dissipation, stiffness and strength to building structures. Up to date, the Egyptian code has no specifications for estimating the response modification factor (R-factor) of structures equipped with BRBs. The only available alternative for BRB design is to use the R-factor of conventional bracing which is equal to 4.5.This study evaluates the R-factors of low– to mid-rise buckling restrained braced frames (BRBFs) designed according to the Egyptian code. Three BRBFs with 3-, 6- and 12-stories are designed with an R-factor of 4.5. The actual R-factors of the frames are evaluated by conducting static pushover and earthquake time history analyses. The results obtained indicate that the R-factors of the BRBFs considered in this study vary from 5.0 to 13.5 in case of static pushover analysis and from 6.7 to 9.1 in case of earthquake analysis. These static and dynamic ranges of the R-factor are higher than the R-factor of 4.5 specified by the Egyptian code for the design of braced steel frames.

The Feasibility of Using Marble Cutting Waste in a Sustainable Building Clay Industry

This study evaluates the feasibility of stabilizing clay bricks with marble cutting waste (MCW). This waste is currently discarded in huge quantities as sludge resulting from the sawing of marble blocks to slabs and the processes of disposing of grinding and polishing marble in landfills located around the marble processing factories in the Shaq El-Thoban industrial zone, Cairo governorate, Egypt, which causes negative impacts on the environment, health, and sustainable development. Experimental investigations were carried out to explore the effect of the addition of MCW in different clay–base mixes using varying percentages of up to 20% at the expense of the hydrated lime. Cement, hydrated lime, and MCW are the three types of solidification agents used, and clay and sand were also added in the formulations of the unfired clay brick specimens. Laboratory cylindrical stabilized and compressed specimens were made; then, they were cured in a humidity chamber for two weeks and four weeks. Afterwards, they were air dried, tested, and evaluated according to the Egyptian code for the building by the stabilized and compressed earth soil (ECBS, 2016). To enhance the durability of the cured specimens, transparent silicon-based paint was used. The results demonstrated that the optimum content of marble sludge waste (MCW) was 15% when used as replacement for hydrated lime in the production of stabilized clay brick. For all of the samples, the use of silicon-based paint was found to improve the strength and water resistance of the stabilized clay bricks. The use of local waste materials as a substitute for a hydrated lime binder reduces both the cost and environmental impact associated with block production.

Analyzing Termination for Convenience Provisions under Common Law FIDIC Using a Civil Law Perspective

The Egyptian government is investing massive sums of money in several large-scale infrastructure projects that are executed by international contractors. Most contracts for such projects are based on the standard conditions of contract for international projects published by the International Federation of Consulting Engineers (FIDIC). However, the economy in Egypt is currently facing some instability and challenges. Due to that, an employer may prefer to include a clause that entitles the employer to bring the contract to an end for the employer’s own convenience. Although Egypt is a civil law jurisdiction, the FIDIC contract is based on legal concepts rooted in the common law system. Thus, international contractors—who use the FIDIC contract in Egypt—must understand how the FIDIC’s termination for convenience provision is interpreted and applied in a civil law country. To do so, a multistep methodology was utilized. First, the paper separately studies provisions of termination for convenience under the FIDIC 1999 Red Book [FIDIC (CONS)], and similarly under the Egyptian Civil Law (ECL). Second, the authors critically analyze the application of the studied provision of the FIDIC (CONS) in the context of the ECL as the applicable law of the contract. On the basis of the analysis, it is concluded that conditions related to the employer’s entitlement to termination for the employer’s convenience in the FIDIC (CONS) resemble those in the ECL; however, the conditions in the ECL are more advantageous to the contractor due to the existence of the provision for loss of profit in the compensation for damages to which the contractor would be entitled under such termination and the absence of such provision under the FIDIC (CONS). Moreover, the paper provides some recommendations for amendments to be made to the Egyptian Civil Code (ECC) and to the FIDIC (CONS) in relation to the termination for convenience provision. This research should help international contractors understand how the FIDIC’s termination for convenience provisions apply to their projects in Egypt. This would minimize, as much as possible, disputes associated with and/or resulting from such provision. Further, this study is beneficial to other Middle East countries since most of them follow civil law jurisdictions that are heavily influenced by the ECL.

Minimum shear reinforcement for ultra-high performance fiber reinforced concrete deep beams

This research aimed to study the minimum requirements of shear reinforcement for ultra high performance fiber reinforced concrete deep beams. The experimental results showed that increasing the provided vertical web reinforcement ratio has slight effect on the diagonal cracking strength and the ultimate shear strength. The maximum spacing between the vertical web reinforcement required by ACI 318-2014 for reinforced concrete beams (d/5) is not suitable for ultra-high performance fiber reinforced concrete deep beams, while for the EC-2 (2b) and that required by the Egyptian code ECP-203-2017 (200 mm) is applicable. The recommendations of AFGC-2013 and KCI-2012 are safe and conservative more than that required by ACI 318-2014.

Evaluating the Response Modification Factors of RC Frames Designed with Different Geometric Configurations

The response modification factor (R-factor) of reinforced concrete (RC) moment resisting frames (MRFs) designed with adequate ductility in accordance with the Egyptian code is evaluated. Static pushover and earthquake time history analyses are employed to determine the actual R-factors of nine RC-MRFs with different geometric configurations. The geometric configuration parameters considered include the number of stories, the number of bays, the bay-width and the story height. The results obtained in this study indicate that the R-factor value decreases with the increase in the frame height and that the changes in the number and span of bays have a minor effect on the R-factor. The R-factors calculated by earthquake analysis are generally smaller than the corresponding values calculated by static pushover loading. The R-factors calculated for the frames considered in this study vary from 6.18 to 9.85 in case of static analysis and from 5.43 to 8.43 in case of earthquake analysis. The minimum limit of the calculated R-factors is smaller than the R-factor of seven specified by the Egyptian code for the design of RC-MRFs with adequate ductility.

Structure Behavior of Beams Combining Ultra High Strength Concrete and Normal Strength Concrete

The concept of "Composite structures or partial elements" was mainly carried out from an economical point view. The basic idea for using the composite elements is combining the Normal strength concrete and Ultra High Strength concrete (UHSC) or any recent advanced cementitious material in composite structures in order to exploit the advantages of the two materials in an optimal way. Ultra-high Strength concrete (UHSC) which was used in this research have exceptional material properties, however, their material costs are significantly higher than those of normal strength concretes. It is defined as a concrete which is meeting special combinations of performance and uniformity requirements that cannot always be achieved routinely using conventional constituent materials and normal mixing, placing, and curing practices,(ACI Committee 116). UHSC is characterized by extraordinary mechanical properties and durability properties. The UHSC-Matrix is very brittle material behavior. In this research an experimental program is being carried out to study the behavior of UHSC beams and composite beams using UHSC (141MPa) and Normal strength concrete with studying the effect of different parameters tested under static loads. This program mainly aims to reach to the optimum thickness of ultra-high strength concrete layer in the composite beams, it also aims to make a validation for using the Egyptian code equation for the maximum reinforcement ratio of longitudinal steel in UHSC and composite beams. This paper presents the results of this experimental program, which consists of ten reinforced concrete beams. The main parameters of this program were: longitudinal reinforcement ratio, the type of used concrete and the thickness of UHSC layer. Particular attention is paid to the effect of each variable on the strength enhancement, stiffness degradation, toughness and ductility of the tested beams. Valuable conclusions were obtained from the research results which stated that; in case of high reinforcement steel ratios the optimum thickness of UHSC in the concrete beams cross section should be not less than the third of the cross section depth only in order to achieve the economic point of view.

Application of the ultimate limit states factored strength approach to design of cantilever walls in dry cohesionless soils

Geotechnical design is carried out according to one of two main methods; the Working Stress Design (WSD) and the Limit States Design (LSD) methods. The LSD can be carried out according to two main approaches; the Factored Strength Approach (FSA), and the Factored Resistance Approach (FRA). The use of LSD in Egypt is limited to the design of reinforced concrete structures. The geotechnical design is still based on the WSD method. The updated Egyptian Geotechnical Code will include both methods for a transition period before fully adopting the LSD. This study describes the methodology and results of determination of the partial factors for the limit states FSA for cantilever walls in dry cohesionless soils such that the LSD matches the WSD. These calibrated values are essential for the transition period when both the WSD and LSD design philosophies are applicable. The study recommends a partial factor of 1.25 in the future version of the Egyptian Code for the limit states FSA design of cantilever walls in dry cohesionless soils, which agrees with the current state of practice in different international codes.

Geotechnical Investigations and Estimation of Earthquakes Factors at an Industrial Qift City, Qena, Egypt

The present work dealt with the estimation of geotechnical parameters and earthquakes factors of poultry feed factory project constructing at an industrial Qift city, Qena, Egypt. The geotechnical parameters were including gradation parameters, shear velocity (Vs), shear parameters (frictional angle and cohesion), and allowable bearing capacity. The earthquakes factors were including soil coefficient (S), limits of constant value for elastic response spectrum (TB and TC), and specified value for begin of the constant displacement spectrum (TD). The present study was interested also in an estimation of design ground acceleration (ag). To achieve these objectives, five mechanical wash boreholes were conducted at ten meter depth. Fifty disturbed samples were collected. Geotechnical laboratory tests were carried out like grain size analyses, direct shear box, and shear velocity (Vs). Standard penetration test (SPT) as geotechnical field test was conducted. The results showed that the studied soils were classified as well graded and poorly graded sands (SP and SW) according to the unified soil classification system (USCS). The earthquakes factors including S, TB, TC, and TD were 1.80, 0.10, 0.30, and 1.20 respectively. The ag-value of the studied area was 0.10. According to Egyptian code for vibration and dynamic load foundations, the studied project area was classified as low potential seismic. According to Egyptian code for shallow foundation, the allowable bearing capacity of the studied sands ranging from 1.5 to 3 kg/cm2 at shallow foundation width must be not less than one meter. Shallow foundations like isolated footing or structural mat were recommended.

English

In this research, the reliability level of reinforced concrete short column designed according to Egyptian code was investigated. The ultimate limit-state design method considering material strength-reduction factors and partial factors for load combinations given in the Egyptian code was used to obtain the characteristic values of short column capacity. Component reliability program, COMREL V8.1, was used to obtain the reliability index based on first order reliability method. The probabilistic models of basic variables were based on the European probabilistic model code. The reliability index of short column was computed at different reinforcement ratios and compared to the reliability obtained when using Euro code (1992-2004) and ACI code in design of the same member. The sensitivity of the reliability index for different parameters such as concrete and steel strengths and their coefficients of variation and standard deviation of permanent actions, were investigated. The results showed that the design of short column according to the Egyptian code achieved sufficient level of reliability higher than the other compared international codes. Besides, the reliability index is sensitive to the coefficient of variation of reinforcement steel and permanent action. Key words: Reliability, ultimate limit state design, probabilistic variables.

Axial load capacity of cold-formed steel built-up stub columns

This paper aims to investigate the axial load capacity of innovative cold-formed steel (CFS) built-up stub columns. Four innovative CFS built up section is presented in this paper. Each section is composed of combination of more than two elements as follows: channels, channels with lip, Sigma section and/or plates. The elements of each section are assembled together by using self tapping screws. The concentric axial load capacity of each of the four sections was investigated numerically by using finite element (FE) model using ABAQUS program. The FE model was verified against previous test data. The FE model was used to study different parameters that affect the load capacities of the innovative CFS built-up stub columns, these parameters are: columns profile, steel thickness, steel grade and longitudinal spacing between screws (fasteners), cross sectional area. The axial load capacities obtained from FE models are compared with the perdition of the Effective width (EW) method (available in Eurocode, Egyptian code, American and Australian standards) and direct strength (DS) method (Available in American and Australian standards).