9 Articles Published

1. PROGRESSIVE COLLAPSE POTENTIAL OF EXISTING PRECAST RC BEAM-COLUMN CONNECTIONS – EXPERIMENTAL STUDY

Authors: HUSSEIN M. ELSANADEDY , MOHAMMED A. ALRUBAIDI

Abstract: The recent terrorist attacks around the world have prompted the respective authorities to address the risks to the critical infrastructure. Precast construction has become increasingly common in the Kingdom of Saudi Arabia because of its speed, which is extremely desirable due the current high rate of development in the Kingdom. In general, buildings are extremely vulnerable to progressive collapse if some of the columns are lost due to blast exposure. As precast buildings lack structural continuity and redundancies in the load paths, they are even more susceptible to progressive collapse than cast-in-situ monolithic buildings. Thus, to avoid catastrophic events, it is important to study the likelihood of the progressive collapse of precast structures in the Kingdom. In this study, the behavior of two different half-scale precast specimens were studied experimentally under middle column removal scenario. These specimens were designed to represent the most common types of exiting precas

Keywords: progressive collapse, precast beam-column connection, monolithic connection

Pages: 1 - 6 | DOI: 10.15224/978-1-63248-088-0-21

2. DYNAMIC ANALYSIS OF OFFSHORE STRUCTURES UNDER IMPACT LOAD USING INTERFACE FINITE ELEMENT METHOD

Authors: ANIS A. MOHAMED ALI , JAFFAR A. KADIM

Abstract: The main object of this paper is to fit with high degree of accuracy the true structure response by considering the concept of interface element which is used to simulate three dimensional soil-structure interaction in the dynamic analysis, therefore the dolphin of khor Al-Amaya berth no. 8 is analyzed as a case study. The (p-y), (t-z), and (q-z) curves which are adopted by American Petroleum Institute (API) are used to find normal and tangential interface moduli and end bearing modulus. For this purpose, a computer Fortran program Offshore_Inter has been built to obtain the required solution. The subspace iteration method is used to find the free vibration solution while Newton-Raphson modified method combined with Newmark’s method is applied to get the nonlinear forced vibration solution. For both solutions, the conjugate gradient algorithm is used as a solver of the dynamic problem. A parametric study has been carried out including different soil type, soil engineering properties, l

Keywords: merican Petroleum Institute API, Newmark’s method, Conjugate gradient algorithm, Reese solution, Winkler method, Pile response

Pages: 7 - 12 | DOI: 10.15224/978-1-63248-088-0-22

3. STRUCTURAL BEFAVIOR OF REINFORCED CONCRETE SHELL WITH STIFFENER UNDER PRESSURE

Authors: TAKASHI HARA

Abstract: Reinforced concrete cylindrical shell with edge beam on meridional free edges was analyzed by use of FEM. As the edge beam on meridional edge, three kinds of rectangular beams were arranged. One was connected to the shell at the gravity center of the beam and the others were connected at the bottom or the top of the beam. The model was supported at four corner of R/C shell. Applied load was the external pressure. From the numerical analyses, the shell connected with the top of the beam showed the smooth deformation and the stress distributions as well as the highest load carrying capacity.

Keywords: FEM, RC shell, beam arrangement, stiffening, cutting edge, deformation, crack

Pages: 13 - 16 | DOI: 10.15224/978-1-63248-088-0-23

4. IMPACT OF ENERGY EFFICIENT CONSTRUCTION DETAILS ON SEISMIC RESISTANCE OF PASSIVE BUILDINGS

Authors: BORIS AZINOVIC , DAVID KOREN , VOJKO KILAR

Abstract: Recently, an increasing trend of passive and lowenergy buildings transferring from non-earthquake prone to earthquake-prone regions has thrown out the question about the seismic safety of such buildings. The paper describes two most commonly used structural details of energy efficient construction, which could be critical from the point of view of earthquake resistance: i) Foundation of a building on thermal insulation (TI) layers and ii) Fixing of precast balcony element without thermal bridge. The first part of the paper describes the problematics of founding of a building on TI and presents the authors’ proposal of seismic fuse assembled out of TI boards and waterproofing (foil) layers, which have been commonly used under the RC foundation slabs of passive buildings. The main idea is to reduce the seismic forces on the superstructure by allowing controlled lateral sliding between the individual layers of the TI boards. The feasibility of the proposed solution has been analysed by me

Keywords: earthquake response, extruded polystyrene (XPS), foundations on thermal insulation layer, low-energy buildings, seismic analysis, thermal bridge, cantilever structures, precast elements

Pages: 17 - 21 | DOI: 10.15224/978-1-63248-088-0-24

5. EVALUATION OF GEOSYNTHETIC-REINFORCED SOIL WALL USING LIMIT EQUILIBRIUM ANALYSES

Authors: ANWAR A. E. AHMED , SULIMAN B. A. MOHAMED

Abstract: Current FHWA design guidelines recommend the lateral earth pressure method for designing reinforced walls (face inclinations larger than 70o) and the limit equilibrium (LE) method for designing reinforced slopes (face inclinations less than 70o); however, this limitation is somewhat arbitrary and there is no clear reason why LE method could not be theoretically applicable to the design of reinforced walls. Therefore, this study evaluated the use of LE for predicting the failure of centrifuge geosynthetic-reinforced soil (GRS) wall models. The variables considered in the centrifuge testing program were the reinforcement types, lengths, spacing, and height of the wall models. The comparison results indicated that LE with a noncircular failure surface and centrifuge models had good agreement in locating failure surfaces. Insoil/ confined ultimate tensile strengths Tult of reinforcements were back-calculated from LE analyses at wall failure (FS=1.0) and consistent confined Tult values were

Keywords: Geosynthetic-reinforced soil wall, Limit equilibrium analysis, Centrifuge model.

Pages: 22 - 27 | DOI: 10.15224/978-1-63248-088-0-25

6. OPTIMUM MANAGEMENT OF GROUNDWATER, USING GENETIC ALGORITHM TECHNIQUE

Authors: ALI H. AL-ABOODI , SARMAD A. ABBAS , WISAM S. AL-REKABI

Abstract: The aim of this research is to develop decision support tools for identifying optimal location for groundwater development to meet the future demands in the Teeb Area. Teeb Area is located in north and north east of Missan Province, south of Iraq. This area is about 1860 km2. A twodimensional mathematical model is developed to simulate the flow regime of the upper part of Quaternary Deposits. The suggested conceptual model, which is advocated to simulate the flow regime of aquifer is fixed for one layer, i.e. the activity of the deeper aquifer is negligible. The model is calibrated using trial and error procedure in two stages, steady state followed by unsteady state. This model is integrated with an optimization model which is based on the genetic algorithm (GA). Three management cases were undertaken by running the model with adopted calibrated parameters. In the first case found the optimum value of the objective function is (0.32947E+08 m3/year), in other words, the pumping rates c

Keywords: Management, Groundwater, Teeb, Genetic Algorithm

Pages: 28 - 36 | DOI: 10.15224/978-1-63248-088-0-26

7. STRUCTURAL PARAMETERS UNCERTAINTIES EFFECT ON STRUCTURAL RESPONSES

Authors: MOHAMMAD S. MIAH

Abstract: Smart structures are adopting the sensorization and leading the structural systems into a non-trivial situation. Hence those structures required complex monitoring, controlling and updating techniques. In order to understand the changes over time of such systems it is essential to understand the effect of uncertainties. There are several known and unknown sources of uncertainties such as environmental variation which may alter the frequencies of the structures as a results they might encounter severe problems or even full collapse. In order to get the best out of the implemented technologies it is necessary to understand the uncertainties issues related to structural properties i.e., stiffness, damping and mass. Additionally, the structural systems required proper treatment as they will essentially handle extreme unknown dynamic loads. For adapting with the aforementioned changes system parameters need to be identified and updated/adjusted throughout their life time. As dynamic loads a

Keywords: Dynamic Loads, Unscented Kalman Filter, Unicertainties, System Identification, Smart Structures.

Pages: 37 - 41 | DOI: 10.15224/978-1-63248-088-0-27

8. EMPIRICAL CORRELATIONS AMONG LIQUID LIMIT, CLAY FRACTION, AND SPECIFIC SURFACE AREA FOR KAOLIN AND CALCIUM BENTONITE COMPOUNDED SAMPLES

Authors: BUDIJANTO WIDJAJA , CLAUDIA BERNADETTE INKIRIWANG

Abstract: Specific surface area (SSA) is one of the engineering properties of clayey soils. This property is highly related to the particle size, strength, compressibility, and permeability of soils. Particle size (i.e., clay fraction) is the most important physical property of clay minerals. Liquid limit (LL), as one of Atterberg’s limit, is also an important index to classify fine-grained soils. Kaolinite (non-expansive soils) and calcium bentonite (expansive soils) are selected as primer soils, and 0% to 40% sand is added to each soil to reduce clay fraction. These ten representative samples are then tested using the BET method to determine the SSA. The SSA of ten compounded samples of kaolinite and calcium bentonite are in the range of 16.2 m2/g–18.8 m2/g and 58 m2/g–69 m2/g, respectively. Results also show that the increase in clay fraction is accompanied by an increase in the SSA of both kaolin and bentonite. The increase in LL is also accompanied by an increase in SSA. The empirical corre

Keywords: BET, clay, calcium bentonite, kaolin, specific surface area, permeability

Pages: 42 - 44 | DOI: 10.15224/978-1-63248-088-0-28

9. THE SOLIDIFICATION EFFECTS OF ADMIXING ACTIVATED STEEL SLAG WITH DREDGED MARINE SILTS

Authors: CHEE-MING CHAN

Abstract: Regular dredging works are necessary for the development of coastal regions and the maintenance of shipping channels. However indiscriminate disposal of the dredged soils in open waters can cause severe and irreversible impact on the marine ecosystem. It is therefore desirable to transform the otherwise waste material into reusable soils, though some form of pre-treatment is necessary to improve the material’s strength and stiffness. This paper describes an exploratory work of admixing dredged marine sediments of predominantly silt contents with activated steel slag for improvement of the mechanical properties. By first identifying the optimum activation concentration of NaOH for the steel slag, the solution was next introduced to the soil-slag mixture for uniform blending. Specimens were prepared per dry weight at ratios of clay : steel slag = 3:7, 5:5 and 7:3, then left to cure for up to 4 weeks. At intervals of 3, 7, 14 and 28 days, bender element and unconfined compressive strength

Keywords: dredged soils, solidification, steel slag, strength, stiffness, bender element

Pages: 45 - 53 | DOI: 10.15224/978-1-63248-088-0-68