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An experimental and numerical program is carried out in this research to investigate the influence of CFRP sheets on the cyclic behavior of unconfined connections made with recycled concrete. Cement is partially replaced by silica fume, iron filling and pulverised fuel ash using two different percentages: 15% and 20%. Each specimen is partially loaded at the first stage and then specimens are repaired using CFRP sheets. The repaired specimens are then laterally loaded until failure. In addition, a finite element model is built in ABAQUS and verified using the experimental results. The experimental results have shown that the repaired specimens have regained almost double the capacity of the un-repaired specimens and hence the adopted repair configuration is recommended for retrofitting seismically vulnerable RC connections. Increasing cement replacement percentage by silica fume, fuel ash or iron filling from 15% to 20% has reduced joint carrying capacity and weakened the joint. It is recommended using 15% pulverised fuel ash or silica fume as cement partial replacement to enhance the strength and ultimate drift of beam-column joints under cyclic loading. Iron filling concrete is also recommended but the enhancement is relatively less than that found with pulverised fuel ash concrete and silica fume concrete.

The unconfined compressive strength (UCS) of soils is essential for both researchers and practitioner geotechnical engineers. UCS is well-understood and standardized for laboratory and fiel...

Introduction:Although it is a regular duty of geotechnical engineers to evaluate how much shallow foundation settles in the granular soil, there is no well-approved formula for this task. The intent of this research is to develop a formula that is adequately simple to be used in routine geotechnical engineering work but complete enough to address the behavior of granular soil associated with the settlement issue.Methods:Cone penetration test and foundation load test data were used to generate a formula that can predict the settlement. Genetic Programming (GP) based Symbolic Regression (GP-SR) and artificial neural networks were used to develop an optimized formula. Settlements were also calculated using the finite method and compared to the results of the developed formula.Results and Conclusion:Two formulas were developed using SR, and several models were developed using ANN. ANN model 1 has the highest R2value (0.93) and the lowest MSE (0.16) among all developed ANN and GP-SR models. FEM settlements were almost double the measured ones in some instances.

An empirical model, which predicts the shear strength of interior reinforced concrete (RC) joints exposed to cyclic loading, is developed using gene expression programming (GEP). Five main parameters are used to develop the GEP model including concrete compressive strength, joint transverse reinforcement, beam reinforcement ratio, joint aspect ratio, and joint width. A large database including 160 data test points is used to test and train the GEP model. The GEP model is then evaluated using the coefficient of determination (R2). The formulation proposed by ACI-352 is used to predict the shear strength of RC joints. The R-squared values of the ACI and the GEP model are 66% and 87% respectively which indicates that the joint shear strength predicted using the GEP model is closer to the experimental results than that predicted using the ACI-352 formulation.

Using a mechanically stabilized earth (MSE) wall as a bridge abutment has become an attractive option to the traditional cast-in-place wall abutment. The use of an MSE wall abutment notably...

This research investigates the behavior of unconfined RC connections made with sustainable concrete under cyclic loading. Different types of sustainable concrete are used where cement is partially replaced by silica-fume, iron filing and pulverized fuel ash using two different percentages 15% and 20%. The numerical finite element model, which simulates the cyclic behavior of RC connections, is verified using the experimental results and can reasonably predict joint response and its damage pattern. Test results have shown that beam-column connections made with iron filings-concrete are significantly damaged when exposed to cyclic loading while others made with silica fume concrete and fuel ash-concrete are stronger and experience minor cracks. Increasing cement replacement percentage from 15% to 20% for any waste material reduces sustainable concrete compressive strength and weakens the joint.

The use of drilled shafts to stabilize an unstable slope has gained popularity in highway applications, mainly because it is a structural fix that does not require additional right-of-way. An analysis method for determining the factor of safety of a drilled shaft or slope system and for determining the earth thrust on the drilled shafts for structural design is introduced. The concept of the analysis is cast in the limiting equilibrium approach via the method of slices, while incorporating the drilled shaft–induced arching effects as the soil mass moved downslope and around the drilled shafts. The mathematical equations based on the limiting equilibrium calculation, together with the load transfer factor for accounting for the drilled shaft–induced arching effects, are presented. The three-dimensional finite element model parametric study using ABAQUS program was used to derive the semiempirical equations for quantifying the arching effect. A UASLOPE computer program was written to incorporate these algorithms for applications to real cases. A case study of a fully instrumented and monitored slope stabilization project, ATH-124, in Ohio, is presented. The analysis of the slope at the project site using finite element modeling and the computer code UASLOPE is presented, together with field-monitored data. On the basis of field monitoring data and the comparison between the finite element analysis results with the computer code UASLOPE results, the suggested analysis and design approach appears to be reasonable.

The soils in the area of the Phoenix Sky Harbor International Airport (PSHIA) generally consist of alluvial sand, gravel, and cobbles (locally known as SGC) deposited by the Salt River. The conventional methods for axial capacity determination, which mostly come from experience with different types of soils, may not be appropriate for these ground conditions. An Osterberg cell load test was performed to obtain accurate site information on side shear and end bearing ultimate capacities of the drilled shafts. Comparisons were developed between predicted axial capacities of drilled shafts using several design methodologies, the axial capacity measured from static load testing, and the finite element method. Where high percentages of gravel and cobbles were encountered, the side friction was significantly underestimated by design equations commonly used. The load test results showed that underestimation of the side shear is evident; therefore design criteria, as well as the methods used for obtaining soil param., should be revisited.

A case study of a slope stabilization project using a single row of rock socketed drilled shafts is presented in this paper. The design method, instrumentation program, and slope/drilled shafts monitoring results are presented. The slope is instrumented with inclinometers to obtain soil movement, piezometers to observe the GWT line, and soil pressure cells to measure earth pressures in different zones. Two drilled shafts are instrumented with an inclinometer in each one to measure the shaft deflection. Furthermore, strain gages and pressure cells were also embedded in the drilled shafts to measure the strain in the longitudinal reinforcement and contact earth pressures at the contact interface between the shaft and the soil. Observations and conclusions regarding the effectiveness of drilled shafts in stabilizing the reconstructed roadway embankment are presented.