Engineering Commons^™

Ensemble-Learning Model Based Ultimate Moment Prediction Of Reinforced Concrete Members Strengthened By Uhpc, Woubishet Zewdu Taffese, Yanping Zhu, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Data-driven model development brings new approaches to solve conventional civil engineering problems, which are usually considered and answered by experimental, analytical, and numerical methods. This study aims to develop an ensemble learning model (i.e., XGBoost: eXtreme Gradient Boosting) to predict ultimate moment of reinforced concrete (RC) members strengthened by a newly developed concrete technology – ultrahigh performance concrete (UHPC). The study considered two scenarios, incorporating eighteen and seventeen features, with one feature modification involving the transformation of width and height to the cross-sectional area of RC members. Incorporating three substrate damage levels, two substrate surface treatments preceding UHPC strengthening, and …

Implementation Of Ground Penetrating Radar (Gpr) And Complementary Non-Destructive Testing On Concrete Structures, Macy Spears

Electronic Theses and Dissertations

This study analyzes the application and practicality of different non-destructive testing (NDT) methods for the inspection of reinforced concrete. There are two studies discussed in this paper. The first one is a laboratory investigation, utilizing ground penetrating radar (GPR) on concrete slabs that consisted of simulated defects to mimic those found in real concrete structures. This served as a preliminary experiment to verify the GPR data with the design of the slabs. The following study describes a field investigation on an old bridge deck, which involved multiple testing methods. The techniques used were GPR, impact echo (IE), ultrasonic pulse echo …

Performance-Based Design Of Rc Columns Using An Equivalent Standard Fire, Robert T. Kuehnen, Maged A. Youssef, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

The extreme variability of natural compartment fires poses a significant challenge in the process of performance-based fire design. To reduce this variability, the severity of a natural fire can be related to that of a standard fire, known as a time equivalent (te). In this paper, the applicability of a time equivalent, previously derived based on the average internal temperature profile (AITP) that develops within reinforced concrete (RC) beams exposed to fire from three sides, is examined for RC columns exposed to fire from four sides. A parametric study is presented to examine the suitability of the …

Development Of A Hybrid Thermoplastic Composite And Concrete Deck System, Benjamin T. Smith

Electronic Theses and Dissertations

Reinforced concrete is a widely used structural system in conventional construction. It is used to create beams, columns, slabs, walls, bridge decks, dams, and many other structures. Concrete is a relatively inexpensive material that is much stronger in compression than in tension. This leads to the need to combine concrete with other materials to make an efficient hybrid structure. In conventional construction, steel reinforcing bars (rebar) are often used to carry the tension in the structure, as they are widely available and their design is well understood. There are some situations where rebar is not effective such as highly corrosive …

Aversion And Warning Factors For Assessing Existing Reinforced Concrete Structures, Marcie Van Weerdhuizen

Electronic Thesis and Dissertation Repository

In a world of aging infrastructure, sustainability initiatives require additional investment in the assessment of existing reinforced concrete structures. Reliability-based assessment should minimize costs by reducing conservatism, while ensuring levels of safety equivalent to those for new designs. Current Canadian and US provisions assign target reliability levels for structural assessment based on criteria including occupancy type, expected failure behaviour, and the effect of element failure on the overall structural integrity. These criteria are defined using discrete and qualitative parameter values. It is shown that the true structural conditions can be better represented by verifying the applicability and completeness of these …

Partial Material Strength Reduction Factors For Aci 318, Tong Zhang

Electronic Thesis and Dissertation Repository

The strength reduction factors, phi, defined in ACI 318-14 for different structural actions and elements lead to inconsistent results. This study proposes partial material strength reduction factors for concrete, phi_c, and reinforcing steel, phi_s, that yield similar design strengths and more consistent reliability indices. Three structural actions are investigated: moment; shear; and, combined moment and axial force. The first-order, second-moment method is used to compute reliability indices for moment and shear, and Monte Carlo simulation is used for combined moment and axial force. The statistical parameters assumed for the professional factor for shear strength significantly impact …

The Effect Of Reinforcing Bar Bend Radius On The Strength And Behavior Of Knee Joints, Xitong Zhou, Christopher S. Williams, Hwa Ching Wang

The Summer Undergraduate Research Fellowship (SURF) Symposium

The strut-and-tie method (STM) is used by structural engineers to design discontinuity regions of reinforced concrete structures. Using STM, the stress distribution in a concrete member is expressed as a set of struts, ties, and nodes in a strut-and-tie model. These components are then proportioned and evaluated to develop an appropriate design. One type of node that appears in knee joints (i.e., frame corners) subjected to closing moments is referred to as a curved-bar node. Although curved-bar nodes represent a unique concentration of stresses in a structure, little research focused on curved-bar node design has been conducted. In response to …

Investigating Composite Action At Ultimate For Commercial Sandwich Panel Composite Connectors, Salam Al-Rubaye, Taylor J. Sorensen, Marc Maguire

Faculty Publications

To achieve full or partial-composite action in prestressed concrete sandwich panel walls, the engineer must obtain a percent composite action from a connector manufacturer, making some engineers uncomfortable. Engineers are dependent upon the recommendations given by the connector manufacturers to establish their designs. This project tested six full-scale sandwich panel walls to evaluate the percent composite action of various connectors and compare the results to those provided by the composite connector manufacturers. This study concluded that the reported degrees of composite action from each manufacturer are considered conservative in all instances for the connectors tested in this paper. Additionally, the …

Behavior Of Fire-Exposed Rc Frames Before And After Jacketing, M. Monir M. Ajan Alhadid

Electronic Thesis and Dissertation Repository

Analysis and design of fire-exposed Reinforced Concrete (RC) frames before and after jacketing with concrete layers are commonly performed using prescriptive methods that rely on the concept of fire rating. These methods were developed based on empirical results on individual RC members subjected to certain fire conditions. In typical fire scenarios, the residual capacity, stiffness and thermal deformations affects not only the local performance of each fire-exposed member, but also the load redistribution and global behavior of the entire frame. In terms of fire safety, the philosophy of the new building codes considers objective-based design as an alternative of the …

Strength Of Reinforced Concrete Beams With High-Strength Steel, Brian C. Rogers, Aishwarya Puranam, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

Structures are commonly made of reinforced concrete, which is a composite material made of concrete and steel reinforcement. Using high-strength steel, with yield stress larger than 100 ksi, could help reduce the quantity of steel required in structural members, thus reducing costs and improving constructability. The hypothesis being tested is that smaller quantities of high-strength steel reinforcement (HSSR) can be used in place of conventional steel in reinforced concrete beams while maintaining similar strength and deformation at failure. Two reinforced concrete beams with two different types of longitudinal steel reinforcement were constructed. The beams were 18 in. wide, 30 in. …

High Strength Steel In The Reinforced Concrete Structures: Serviceability, Alan Kanybek, Aishwarya Puranam, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

The use of high-strength steel (yield stress larger than 100 ksi) in reinforced concrete structures can provide an effective alternative to using conventional steel (yield stress up to 80 ksi). The goal of this study is to investigate if slabs with reduced quantities of high-strength steel reinforcement meet the serviceability criteria. Instantaneous and long-term deflections in slab specimens with conventional steel and reduced amounts of high-strength steel (as compared with conventional steel) were studied. Two sets of two reinforced concrete slabs, each 14 ft. long, 30 in. wide, were built. The depth, quantity, and type of longitudinal reinforcement were varied …

Durability-Based Optimal Design Methodology For Rc Members In Corrosive Environment, Saeid A. Alghamdi, Shamsad Ahmad, Adamu Lawan

International Conference on Durability of Concrete Structures

No abstract provided.

Behaviour Of Reinforced Concrete And Composite Conical Tanks Under Hydrostatic And Seismic Loadings, Ahmed Elansary

Electronic Thesis and Dissertation Repository

Conical liquid storage tanks are widely used to store different liquids and to provide water supply at cities and municipalities. However, no comprehensive guidelines currently exist in the codes of practice for the structural analysis and design of such tanks. The walls of a conical tank can be made of steel, reinforced concrete, or a combination of the two materials in a composite type of construction in which steel and concrete walls are connected using steel studs. The research conducted in this thesis provides a comprehensive understanding of the structural behaviour of reinforced concrete and composite conical tanks under hydrostatic …

Circular Rc Columns Partially Confined With Frp, Sahar Y. Ghanem

Theses and Dissertations--Civil Engineering

Wrapping reinforced concrete (RC) columns with Fiber Reinforced Polymer (FRP) composites is effective in increasing their capacity. The current state of art concentrates primarily on fully wrapped RC columns and few studies dealt with partially wrapped columns. The majority of the studies did not account for the influence of the existing steel reinforcement on the column’s behavior. Other studies estimated the total confinement pressure as the sum of the confinement pressure due to the external FRP jacketing and due to the internal transverse steel reinforcement. Few models dealt with the coupled effect of the confinement from steel and partial FRP …

Straining Definitions, William Pollalis, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

The concept of strain is ubiquitous in engineering textbooks. It is defined early in engineering education as change in length divided by initial length, and is used to quantify deformations due to things like stresses and temperature changes. The concept itself is quite straightforward and represents homogenous materials well, but homogenous materials are rarely present in engineering design. Composite materials such reinforced concrete cannot be simply defined, as their properties are heavily influenced by their non-uniformity. For example, there are large deformations around tensile cracks in reinforced concrete, where the reinforcement withstands all the tensile stress, and little deformation in …

Shear Capacity Of Rc Beams At Elevated Temperatures, Maged A. Youssef, Mohamed Diab, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

Fire safety is a critical criterion for designing reinforced concrete structures. With the introduction of performance-based design, structural engineers need design tools to assess the capacity of different elements during fire exposure. This paper proposes an analytical method to predict the shear capacity of reinforced concrete beams exposed to elevated temperatures. The proposed method extends the use of existing ambient temperature methods by accounting for the effect of elevated temperatures on material properties. It involves heat transfer analysis, evaluation of the material properties at elevated temperatures, and application of the modified compression field theory to estimate the shear capacity. The …

Shear Capacity Of Reinforced Concrete Beams At Elevated Temperatures, Mohamed Diab

Electronic Thesis and Dissertation Repository

Fire safety is an important design aspect that ensures structural integrity of a Reinforced Concrete (RC) building during fire events. As new codes are moving from prescriptive methods to performance-based methods, design engineers are in need of rational design tools to assess the capacity of RC elements during a fire event. Previous research work focused on the flexural and axial capacities of concrete elements exposed to fire. Research addressing the shear capacity of concrete elements exposed to fire is limited in the literature.

An analytical method to predict the shear capacity of RC beams exposed to elevated temperatures is proposed. …

Second-Order Analysis Of Cable-Stayed Bridge Deck Slabs, Zachary Mcneil

Electronic Thesis and Dissertation Repository

Current provisions in CSA S6-06 “Canadian Highway Bridge Design Code” for computing second-order effects in slender concrete beam-columns were derived for columns in buildings, where these effects can often be neglected, so their applicability to extremely slender cable-stayed bridge decks warrants investigation. The research reported in this thesis first reviews the provisions in CSA S6-06, as well as eight equations proposed by others, for computing the flexural rigidity, EI, of slender concrete beam-columns. Methods for quantifying the rotational restraint provided at deck slab supports by steel or concrete floorbeams are presented and validated: steel floorbeams provide negligible restraint but …

Reliability Analysis Of Rc Beams Exposed To Fire, Christopher D. Eamon, Elin A. Jensen

Civil and Environmental Engineering Faculty Research Publications

A procedure for conducting reliability analysis of reinforced concrete beams subjected to a fire load is presented. This involves identifying relevant load combinations, specifying critical load and resistance random variables, and establishing a high-temperature performance model for beam capacity. Based on the procedure, an initial reliability analysis is conducted using currently available data. Significant load random variables are taken to be dead load, sustained live load, and fire temperature. Resistance is in terms of moment capacity, with random variables taken as steel yield strength, concrete compressive strength, placement of reinforcement, beam width, and thermal diffusivity. A semi-empirical model is used …

Strengthening Of Rural Bridges Using Rapid-Installation Frp Technology: Route 63 Bridge No. H356, Phelps County, Dongming Yan, Jianbo Li, Chenglin Wu, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This report presents the use of externally bonded fiber reinforced polymers (FRP) laminates for the flexural strengthening of a concrete bridge. The bridge selected for this project is a two-span simply supported reinforced concrete slab with no transverse steel reinforcement located in Phelps County, MO. The original construction combined with the presence of very rigid parapets caused the formation of a 1-inch wide longitudinal crack, which resulted in the slab to behave as two separate elements. The structural behavior was verified using a finite element model (FEM) of the bridge. The bridge analysis was performed for maximum loads determined in …

Damage Characterization Of Beam-Column Joints Reinforced With Gfrp Under Reversed Cyclic Loading, Aly M. Said

Civil and Environmental Engineering and Construction Faculty Research

The use of fiber reinforced polymer (FRP) reinforcement in concrete structures has been on the rise due to its advantages over conventional steel reinforcement such as corrosion. Reinforcing steel corrosion has been the primary cause of deterioration of reinforced concrete (RC) structures, resulting in tremendous annual repair costs. One application of FRP reinforcement to be further explored is its use in RC frames. Nonetheless, due to FRP's inherently elastic behavior, FRP-reinforced (FRP-RC) members exhibit low ductility and energy dissipation as well as different damage mechanisms. Furthermore, current design standards for FRP-RC structures do not address seismic design in which the …

Behaviour Of Reinforced Self-Consolidating Concrete Frames, Aly Said, Moncef Nehdi

Civil and Environmental Engineering and Construction Faculty Research

Multi-storey reinforced concrete (RC) structural frames represent some of the most congested structural elements. Placing and consolidating concrete in such structural frames imposes substantial challenges. This offers a unique area of application for self-consolidating concrete (SCC) because of its inherent ability to flow under its own weight and fill congested sections, complicated formwork and hard-to-reach areas. Research is, however, needed to demonstrate the ability of SCC structural frames adequately to resist vertical and lateral loads. In the present study, full-scale 3 m high beam-column joints reinforced as per the Canadian Standards CSA A23·3-94 and ACI-352R-02 were made with normal concrete …

Nonlinear Model For Reinforced Concrete Under Cyclic Loading, Aly Said, M. Elmorsi, M. Nehdi

Civil and Environmental Engineering and Construction Faculty Research

Most of the available shear models for reinforced concrete rely on empirical formulations. In this study, a rational shear stress function is used to define the shear stress–strain envelope for reinforced concrete. Cyclic rules are proposed to define the loading, unloading and reloading relationships for reinforced concrete under shear stress reversals. A normal stress function describing the cyclic relationship of concrete under axial stress is also introduced. The proposed functions are verified using experimental data of reinforced concrete panels tested under monotonic and cyclic loading. Subsequently, the normal and shear stress functions along with their cyclic rules are integrated in …

Influence Of Connection Placement To The Behavior Of Precast Concrete Exterior Beam-Column Joint, Elly Tjahjono, Heru Purnomo

Makara Journal of Technology

Influence of Connection Placement to the Behavior of Precast Concrete Exterior Beam-Column Joint. This paper presents an experimental study on the influence of connection placement to the behaviour of exterior beamcolumn joint of precast concrete structure under semi cyclic loading. Four half-scale beam-column specimens were investigated. Three beam-columns were jointed through connection that are placed in beam-column joint region and the forth is connected at the plastic hinge potensial region of the beam. Crack patterns, strength, stiffness and ductility of the test specimens have been evaluated. The test result indicated that all beam-column specimens show good ductility behavior.