Richard E. Klingner

Bio: Richard E. Klingner is an academic researcher from University of Texas at Austin. The author has contributed to research in topics: Masonry & Girder. The author has an hindex of 20, co-authored 82 publications receiving 1888 citations.

Structural Modeling and Experimental Techniques

Abstract: Introduction to Physical Modeling in Structural Engineering Introduction Structural Models - Definitions and Classifications A Brief Historical Perspective on Modeling Structural Models and Codes of Practice Physical Modeling and the New Engineering Curriculum Choice of Geometric Scale The Modeling Process Advantages and Limitations of Model Analysis Accuracy of Structural Models Model Laboratories Modeling Case Studies The Theory of Structural Models Introduction Dimensions and Dimensional Homogeneity Dimensional Analysis Structural Models Similitude Requirements Elastic Models - Materials and Techniques Introduction Materials for Elastic Models Plastics Time Effects in Plastics - Evaluation and Compensation Effects of Loading Rate, Temperature, and the Environment Special Problems Related to Plastic Models Other Common Elastic Model Materials Balsa Wood, Structural Wood, and Paper Elastic Models - Design and Research Applications Determination of Influence Lines and Influence Surfaces Using Indirect Models - Muller-Breslau Principle Inelastic Models: Materials for Concrete and Masonry Structures Prototype and Model Concretes Engineering Properties of Concrete Unconfined Compressive Strength and Stress-Strain Relationship Tensile Strength of Concrete Flexural Behavior of Prototype and Model Concrete Behavior in Indirect Tension and Shear Design Mixes for Model Concrete Summary of Model Concrete Mixes Used by Various Investigators Gypsum Mortars Modeling of Concrete Masonry Structures Strength of Model Block Masonry Assemblages Inelastic Models: Structural Steel and Reinforcing Bars Introduction Steel Structural Steel Models Reinforcement for Small-Scale Concrete Models Model Prestressing Reinforcement FRP Reinforcement for Concrete Models Bond Characteristics of Model Steel Bond Similitude Cracking Similitude and General Deformation Similitude in Reinforced Concrete Elements Model Fabrication Techniques Introduction Basic Cutting, Shaping and Machining Operations Basic Fastening and Gluing Techniques Construction of Structural Steel Models Construction of Plastic Models Construction of Wood and Paper Models Fabrication of Concrete Models Fabrication of Concrete Masonry Materials Instrumentation Principles and Applications General Quantities to Be Measured Strain Measurements Displacement Measurements Full-Field Strain Measurements and Crack Detection Methods Stress and Force Measurement Temperature Measurements Creep and Shrinkage Characteristics and Moisture Measurements Data Acquisition and Reduction Fiber Optics and Smart Structures Loading Systems and Laboratory Techniques Introduction Types of Loads and Loading Systems Discrete vs. Distributed Loads Loading for Shell and Other Models Loading Techniques for Buckling Studies and for Structures Subject to Sway Miscellaneous Loading Devices Size Effects, Accuracy and Reliability in Materials System and Models General What Is a Size Effect? Factors Influencing Size Effects Theoretical Studies in Size Effects Experimental Work in Plain Concrete Size Effects in Reinforced and Prestressed Concrete Size Effects in Metal and Other Materials Size Effects in Masonry Mortars Size Effects and Design Codes Errors in Model Studies Types of Errors Statistics of Measurements Propagation of Random Errors Accuracies in (Concrete) Models Overall Reliability of Model Results Influence of Cost and Time on Accuracy of Models Model Applications and Case Studies Introduction Modeling Applications Case Studies Structural Models for Wind, Blast, Impact and Earthquake Loads Introduction Similitude Requirements Materials for Dynamic Models Loading Systems for Dynamic Model Testing Examples of Dynamic Models Case Studies Educational Models for Civil and Architectural Engineering Introduction Historical Perspective Linearly Elastic Structural Behavior Nonlinear and Inelastic Structural Behavior Structural Dynamics Concepts Experimentation and the New Engineering Curriculum Case Studies and Student Projects

Behavior of post-installed shear connectors under static and fatigue loading

Abstract: This paper describes a series of tests investigating methods to develop composite action in existing non-composite floor systems. Three types of 22-mm diameter post-installed shear connectors were tested under static and fatigue loading. Test results are compared with previous research results on 19-mm diameter, post-installed shear connectors as well as with conventional welded shear studs. Based on the test results, preliminary design equations are proposed for the static and fatigue strength of post-installed shear connectors. These post-installed shear connectors showed a significantly higher fatigue strength than conventional welded shear studs. The superior fatigue strength of these post-installed shear connectors enables the strengthening of existing bridge girders using significantly fewer shear connectors than possible with conventional welded shear studs.

Earthquake Resistance of Infilled Frames

Abstract: The experimental phase consists of quasistatic cyclic load tests on one-third scale model subassemblages of the lower three stories of an 11-story, three-bay frame with infills in the two outer bays: (1)Frame members (particularly the columns) are designed for high rotational ductility and resistance to degradation under reversed cyclic shear loads; (2)gradual panel degradation is achieved using closely spaced infill reinforcement; and (3)panel thickness is limited so that the infill cracking load is less than the available column shear resistance. The analytical phase consists of developing relatively simple, macroscopic mathematical models for predicting the experimentally observed bare and infilled frame behavior. The infilled frame model is found to give excellent predictions of observed response. It is concluded that the model developed and the procedure used can be applied to the analytical prediction of the response of large, engineered infilled frame structures to severe lateral forces.

Effect of Tuned-Mass Dampers on Seismic Response

Abstract: A realistic prototype high-rise building was designed and modeled using linear elastic (and also nonlinear) degrading stiffness idealizations. Using an effective damper mass ratio of 0.026, three different techniques were used to design an optimum tuned-mass damper (TMD) for the prototype. All were found to give essentially the same design. The response of the idealized prototype building to a strong ground motion was computed with and without a TMD. The TMD did not reduce the prototype's maximum response. Based on these results, vibration absorbers do not seem effective in reducing the maximum seismic response of tall buildings.

Experimental Behavior of Bridge Beams Retrofitted with Postinstalled Shear Connectors

Abstract: A number of older bridges were constructed with floor systems consisting of a noncomposite concrete slab over steel girders. A potentially economical means of strengthening these floor systems is to connect the existing concrete slab and steel girders with postinstalled shear connectors to permit the development of composite action. This paper presents the results of an experimental investigation of this concept. Five large-scale noncomposite beams were constructed, and four of these were retrofitted with postinstalled shear connectors and tested under static load. The retrofitted composite beams were designed as partially composite with a 30% shear connection ratio. A noncomposite beam was also tested as a baseline specimen. Test results showed that the strength and stiffness of existing noncomposite bridge girders can be increased significantly. Further, excellent ductility of the strengthened partially composite girders was achieved by placing the postinstalled shear connectors near zero-moment regions to reduce slip demand on the connectors. The test results also showed that current simplified design approaches commonly used for partially composite beams in buildings provide good predictions of the strength and stiffness of partially composite bridge girders strengthened using postinstalled shear connectors.

"building code requirements for structural concrete (aci 318-11) and commentary"

Abstract: The “Building Code Requirements for Structural Concrete” (“Code”) covers the materials, design, and construction of structural concrete used in buildings and where applicable in nonbuilding structures. The Code also covers the strength evaluation of existing concrete structures. Among the subjects covered are: contract documents; inspection; materials; durability requirements; concrete quality, mixing, and placing; formwork; embedded pipes; construction joints; reinforcement details; analysis and design; strength and serviceability; flexural and axial loads; shear and torsion; development and splices of reinforcement; slab systems; walls; footings; precast concrete; composite flexural members; prestressed concrete; shells and folded plate members; strength evaluation of existing structures; provisions for seismic design; structural plain concrete; strut-and-tie modeling in Appendix A; alternative design provisions in Appendix B; alternative load and strength reduction factors in Appendix C; and anchoring to concrete in Appendix D. The quality and testing of materials used in construction are covered by reference to the appropriate ASTM standard specifications. Welding of reinforcement is covered by reference to the appropriate American Welding Society (AWS) standard. Uses of the Code include adoption by reference in general building codes, and earlier editions have been widely used in this manner. The Code is written in a format that allows such reference without change to its language. Therefore, background details or suggestions for carrying out the requirements or intent of the Code portion cannot be included. The Commentary is provided for this purpose. Some of the considerations of the committee in developing the Code portion are discussed within the Commentary, with emphasis given to the explanation of new or revised provisions. Much of the research data referenced in preparing the Code is cited for the user desiring to study individual questions in greater detail. Other documents that provide suggestions for carrying out the requirements of the Code are also cited.

Flexible Piezoelectric ZnO–Paper Nanocomposite Strain Sensor

Abstract: The fabrication of a mechanically flexible, piezoelectric nanocomposite material for strain sensing applications is reported. Nanocomposite material consisting of zinc oxide (ZnO) nanostructures embedded in a stable matrix of paper (cellulose fibers) is prepared by a solvothermal method. The applicability of this material as a strain sensor is demonstrated by studying its real-time current response under both static and dynamic mechanical loading. The material presented highlights a novel approach to introduce flexibility into strain sensors by embedding crystalline piezoelectric material in a flexible cellulose-based secondary matrix.

Bolted shear connectors vs. headed studs behaviour in push-out tests

Abstract: Prefabrication of concrete slabs reduces construction time for composite steel–concrete buildings and bridges. Different alternatives for shear connectors (bolts and headed studs) are analysed here to gain better insight in failure modes of shear connector in order to improve competiveness of prefabricated composite structures. Casting of high strength bolted shear connectors in prefabricated concrete slabs offers the higher level of prefabrication comparing to a standard method of grouting welded headed studs in envisaged pockets of concrete slabs. In addition, bolted shear connectors can easily be dismantled together with the concrete slab thus allowing the improved sustainability of the construction, simpler maintenance, and development of modular structural systems. Bolted shear connectors have been rarely used in construction, actually just for rehabilitation works, because there is a lack of design recommendation. The first step towards the design recommendation is to understand the difference between the headed shear studs and the bolted shear connectors in a push-out test. Push-out tests, according to EN1994-1-1, using 4 M16 — grade 8.8 bolts with embedded nut in the same layout and test set-up as for previously investigated headed studs were performed. Finite element models for both shear connectors were created, and good match with experimental data was obtained. Basic shear connector properties such as: shear resistance, stiffness, ductility and failure modes have been compared and discussed in detail by using experimental and FE results. Parametric FE analyses of shear connector's height are carried out and shear resistance reduction factor has been proposed for bolted shear connectors.

Concrete-to-concrete bond strength. influence of the roughness of the substrate surface

Abstract: An experimental study was performed to evaluate the bond strength between two concrete layers, for different techniques for increasing the roughness of the substrate surface. In a total of 25 slant shear specimens and 25 pull-off specimens the substrate surface was prepared by wire-brushing; sand-blasting; chipping with a light jackhammer; or were left as-cast against steel formwork. Three months later, the new concrete was added. Pull-off tests were performed to evaluate the bond strength in tension. Slant shear tests were conducted to quantify the bond strength in shear. Analysis of results indicated that: the highest value of bond strength was achieved with sand-blasting; pull-off tests are adequate to estimate the bond strength in situ; and pre-wetting the substrate surface does not seem to influence the bond strength.

Research developments in vibration control of structures using passive tuned mass dampers

Abstract: A state-of-the-art review on the response control of structures mainly using the passive tuned mass damper(s) (TMD/s) is presented. The review essentially focuses on the response control of wind- and earthquake-excited structures and covers theoretical backgrounds of the TMD and research developments therein. To put the TMD within a proper frame of reference, the study begins with a qualitative description and comparison of passive control systems for protecting structures subjected to wind-imparted forces and forces induced due to earthquake ground motions. A detailed literature review of the TMD is then provided with reference to both, the theoretical and experimental researches. Specifically, the review focuses on descriptions of the dynamic behavior and distinguishing features of various systems, viz. single TMD (STMD), multiple tuned mass dampers (MTMDs), and spatially distributed MTMDs (d-MTMD) which have been theoretically developed and experimentally tested both at the component level and through small-scale structural models. The review clearly demonstrates that the TMDs have a potential for improving the wind and seismic behaviors of prototype civil structures. In addition, the review shows that the MTMDs and d-MTMDs are relatively more effective and robust, as reported. The paper shows the scope of future research in development of time and frequency domain analyses of structures installed with the d-MTMDs duly considering uncertainties in the structural parameters and forcing functions. In addition, the consideration of nonlinearity in structural material and geometry is recommended for assessment of the performance of the STMD, MTMDs, or d-MTMDs.