Master of Science / Department of Architectural Engineering / Kimberly W. Kramer / In structural steel connection design, simple shear connections are one of the most common connection types utilized. The industry, especially from the side of the engineer, tends to lean toward using Double Clip Angle Connections as the default standard for simple shear connections. A double clip angle connection is a connection consisting of two angles transferring the shear forces from one member to the next either through bolts or welds. The design of Double Clip Angle Connections is efficient and the connections themselves are easy to fabricate. However, benefits to utilizing other types of shear connections exist. Many of these benefits are seen in the fabrication shop or during erection and construction. This is especially true of single shear plate or shear tab connections when applied to open structure design. Shear tab connections consist of a single plate that transfers the shear forces from one member to the next with bolts or with welds. The design of shear tab connections can be a more involved process than the design of double clip angles. Sometimes the shear plate or shear tab has to be longer than is typical. This is called an extended shear plate connection. These extended shear plates can bring other variables into the design that typically don’t occur with Double Clip Angle Connections such as bending of the plate or the need for multiple bolt columns. However, with proper planning and detailing, the benefits and savings experienced in the fabrication or construction phase may outweigh what can be seen as a more laborious design task. The purpose of this report is to identify the possible benefits achieved in using each of these connections, highlight the differences in the design approach for each, and use a study model to compare the outcome of using one connection over another in the design of a typical open structure. Double clip angles are typically the most efficient approach when speed of design and simplicity of fabrication are the desired outcomes. However, shear plate or shear tab connections have the potential to provide safer erection alternatives and materials savings if used in appropriate ways and with the right applications.

Fibre reinforced polymer (FRP) composites represent an alternative construction material for deep foundations that have the potential to eliminate most of the durability concerns associated with traditional piling materials. Research studies and database related to the use FRP composite material as piling foundation is very limited. This research project was undertaken to investigate the structural and geotechnical behaviour of FRP composite piles. The originality of this study rests on the following pillars:• Presenting a new understanding for the factors controlling the compressive strength of FRP tube confined concrete. • Introducing the concept of constitutive interface surface which considers the effect of surface hardness and relative roughness on the interface shear coefficient. • Studying the evolution of FRP pile surface roughness during the driving process. • Investigating the effect of harsh environments on the shear behaviour of FRP-granular interface. • Conducting an extensive experimental and numerical study to characterize the FRPs and soil parameters that control the behaviour of axially and laterally loaded FRP composite pile. Experimental testing program was conducted in this study to examine the behaviour of two different FRPs tubes confined concrete under axial compression, and flexural load. Based on the experimental results of this study and test results available in the literature, a new design chart was proposed to predict the strength enhancement based on concrete strength and FRP lateral confinement. An extensive laboratory study was conducted to evaluate the interface friction behaviour between granular materials and two different FRP materials. The interface test results obtained from experiment were used to examine a number of parameters known to have an effect on the interface friction coefficient. Furthermore, to investigate the evolution of FRP pile surface roughness during the driving process laboratory tests were also conducted to quantify the interface shear induced surface roughness changes under increased normal stress levels. Moreover, interface tests were also conducted using three more counterface materials to define schematically the constitutive interface shear surface (CISS) in the three dimensional domain of surface roughness, surface hardness, and interface shear coefficient. The long-term experimental program was also conducted in this study to assess the effect of different ageing environment conditions on FRP-granular interface shear coefficient. Acidic and alkaline aging environments were adopted in this study. The experimental program involved assessing the ageing effect on the testing FRP materials in terms of the changes in their hardness and surface roughness properties. Furthermore, the interface shear tests were conducted, using the unaged and aged FRP materials, to evaluate the effect of aging environments on FRP-granular interface shear coefficient. A small-scale laboratory pile loading tests were carried out to assess the FRP pile behaviour under axial and lateral loads. The laboratory test results were used to verify/validate a numerical model developed by the commercial finite element package ABAQUS (6.11). Additional numerical analyses using the verified model were conducted to investigate the effect of different the FRPs and soil parameters on the engineering behaviour of FRP pile.

Cuenca Asensio, E. (2012). ON SHEAR BEHAVIOR OF STRUCTURAL ELEMENTS MADE OF STEEL FIBER REINFORCED CONCRETE [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18326 / Palancia

The shear behavior of a specimen made of reinforced concrete is complex. The resisting mechanisms are affected by different factors such as section form, slimness of the specimen, longitudinal and transversal reinforcement arrangement, adhesion between concrete and steel, among others. Addition of steel fibers to the concrete improves the ductility as well as the tensile behavior; providing good control during the cracking process. Fibers also enhance the shear behavior of structural elements, increasing ultimate resistance and ductility. Push-off tests had been used to study the mechanisms of concrete shear transfer. Shear strength of the specimen depends on the contribution of both concrete and reinforcement. Aggregate interlock has a significant contribution to the concrete shear capacity. In the last decades new kinds of concrete have been developed for industrial use, such as high strength concrete (HSC), self-compacting concrete (SCC) or fiber reinforced concrete (FRC), among others. In these new materials aggregate interlock phenomenon may be different when compared to conventional concrete (CC). There is a lack of information in literature about the mechanisms of shear transfer in fiber reinforced concrete elements. / Echegaray Oviedo, JA. (2014). Upgrading the push-off test to analyze the contribution of steel fiber on shear transfer mechanisms [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/43723 / TESIS

The diploma thesis deals with the study of Inter-Laminar Shear Strength (ILSS) of polymer composites, based on unsaturated polyester resin with unidirectionally oriented basalt or glass fibers. The basis of the experimental part is the preparation of composite samples with different types of surface treatment of a fibers (a reinforcement) as well as the surface treatment itself. The untreated, the commercially treated fibers and the plasmatreated fibers used as reinforcement in the polymer composites were analysed by a short beam shear test and their ILSS was determined. The effect of various deposition conditions during Plasma-Enhanced Chemical Vapour Deposition (PECVD) on the value of ILSS of the composite with originally unsized glass or basalt fibers was studied. The impact of aging on the interlaminar shear strength of the composites was investigated for commercially treated glass fibers. The Scanning Electron Microscopy (SEM) is also used in the thesis together with the Energy Dispersive Spectroscopy (EDS). Based on all the results a proposal was made to correct and improve the deposition conditions and thus improve the interphase to achieve the required shear properties of polymer composites.

In the cold-formed steel construction, the oriented strand board is a common material for shear wall sheathing. an OSB is made by using wood chips as raw materials that undergo high temperature pressing to create a multi-larger structure material. Due to the OSB having a high strength in shear, it is an important material used in the construction field. the thesis is trying to verify published nominal shear strength in AISI-213-07 in the first part. This objective has two parts: the first part is to verify nominal shear strength (Rn) for wind and other in-plane loads for shear wall. the second part is to verify nominal shear strength (Rn) for seismic and other in-plane loads for shear wall. Secondly, the thesis verifies the design deflection equation for nominal shear strength of CFS shear walls with OSB sheathing. the test specimens were divided into eight groups which trying to verify the design deflection equation that was published in AISI-213-07 standard.

Joints are the main features encountered in rock and sliding of rock blocks on joints is classified as the principal source of instability in underground excavations. In this regard, joints’ peak shear strength is the controlling parameter. However, given the difficulty in estimating it, shear tests are often performed. These are often quite expensive and also time consuming and, therefore, it would be valuable if shear tests could be artificially performed using numerical models. The objective of this study is to prove the possibility to perform virtual numerical shear tests in a PCF2D environment that resemble the laboratory ones. A numerical model of a granite rock joint has been created by means of a calibration process. Both the intact rock microparameters and the smooth joint scale have been calibrated against macroparameters derived from shear tests performed in laboratory. A new parameter, the length ratio, is introduced which takes into account the effective length of the smooth joint compared to the theoretical one. The normal and shear stiffnesses, the cohesion and the tensile force ought to be scaled against the length ratio. Four simple regular joint profiles have been tested in the PFC2D environment. The analysis shows good results both from a qualitative and from a quantitative point of view. The difference in peak shear strength with respect to the one computed with Patton´s formula is in the order of 1% which indicates a good accuracy of the model. In addition, four profiles of one real rough mated joint have been tested. From the scanned surface data, a two-dimensional profile has been extracted with four different resolutions. In this case, however, interlocking of particles along the smooth joint occurs, giving rise to an unrealistic distribution of normal and shear forces. A possible explanation to the problem is discussed based on recent developments in the study of numerical shear tests with PFC2D.

The Icy Springs Bridge in Coalville, Utah carries 2nd South Street over the Weber River west of Interstate 80. The bridge is owned by Coalville City and was originally constructed in 1965 as a single-span 51-foot long bridge using prestressed concrete double-tee girders. In the fall of 2013 the original bridge was replaced with a new 80-foot long single span bridge using prestressed concrete decked bulb-tee girders. The original girders were salvaged and transported to the Systems, Materials, and Structural Health Lab (SMASH Lab) where a series of tests were performed to determine the total losses in the prestressing of the strands, the flexural and shear capacities of the girders, and the punching shear capacity of the reinforced concrete deck. The results of these tests were compared to the values calculated using methods outlined in the 2012 American Association of State Highway and Transportation Officials Load and Resistance Factor Design (AASHTO LRFD) Bridge Design Specifications, the current bridge design code used by most departments of transportation, and a finite element model using the computer program ANSYS. For the shear and punching shear test results, the AASHTO LRFD Bridge Design Specifications was conservative and was able to predict the type of failure that occurred. However, the tested flexural results were below the calculated flexural capacities using the AASHTO LRFD Bridge Design Specifications. A finite element model was created and calibrated to the test results for the various loading and support conditions. The actual tested material properties were compared to the material properties used in the finite element analyses to determine the difference between the actual girders and the theoretical models. Funding for this project was provided by the Utah Transportation Center.

<p>U radu su izvedene diferencijalne jednačine tankozidnog kompozitnog štapa proizvoljnog poprečnog preseka, primenom principa virtualnih pomeranja, a polazeći od funkcije deplanacije koju je predložio A. Prokić, za tankozidne štapove homogenog poprečnog preseka. Ona omogućava jedinstvenu analizu tankozidnih štapova otvorenog i zatvorenog poprečnog preseka, pretpostavka o zanemarenju klizanja u srednjoj površi štapa nije<br />neophodna, pa se smičući naponi određuju direktno iz odgovarajućih deformacija. Raspodela normalnih napona nije više određena sektorskom koordinatom već parametrima pomeranja čvornih tačaka, i u opštem slučaju je promenljiva od preseka do preseka, što omogućuje registrovanje i analizu shear lag uticaja, koji se klasičnom teorijom tankozidnih nosača ne može opisati. Kao što je poznato, shear lag uticaj predstavlja neravnomernu<br />raspodelu normalnih napona u pojasevima, s tim što se maksimalna vrednost javlja na mestu spoja pojasa sa rebrima, i u opštem slučaju je veća od vrednosti napona koja se dobija klasičnom teorijom savijanja štapova zasnovanoj na Bernoullijevoj hipotezi. To je posebno izraženo kod štapova napregnutih na savijanje kod kojih dolazi do značajne deplanacije poprečnog preseka.<br />Dobijeni sistem diferencijalnih jednačina se ne može rešiti u zatvorenom obliku te se pristupilo numeričkoj metodi, odnosno primeni metode konačnih elemenata. Definisana su dva tipa elementa sa različitim polaznim pretpostavkama. Prvi tip elementa zasnovan je na teoriji Timoshenka, odnosno uticaj transverzalnih sila na deformaciju se uzima u obzir. Drugi tip elementa zanemaruje uticaj transverzalnih sila na deformaciju, odnosno usvaja se pretpostavka da poprečni preseci i nakon deformacije ostaju ravni i upravni<br />na srednju liniju štapa. Kao dokaz tačnosti prethodno izvedenih teorijskih razmatranja urađen je niz primera pomoću programa napisanog u programskom jeziku C.</p> / <p>Differential equations of thin-walled composite beams of arbitrary cross section were<br />derived, using the principle of virtual displacements and starting from function of deplanation suggested by A. Prokic, for thin-walled beams of homogeneous cross section. It enables unique analysis thin-walled beams of open and closed cross section, assumption of neglecting shear strain in the middle surface is not necessary and shear stresses can be calculated directly from the strains. Distribution of longitudinal stresses is not defined by warping function, but parameters of longitudinal displacement, and in general case it is variable of section to section, that enables registering and analysis of shear lag, which classical theory of thin-walled beams is unable to reflect. As it is known, shear lag effect presents a non-uniform distribution of normal stresses in the flanges, maximal values are on the connection of flange and web, in general case it is larger from the value of stress obtained by classical theory of beams based on the Bernoulli hypothesis. It is especially<br />expressed at beams subjected to bending where deplanation of cross section is significant. Derived system of differential equations can not be solved in closed form solution and it was accessed to numerical method, respectively on the finite element method. Two types of element with different starting settings were defined. First type of element is based on the theory of Timoshenko, apropos the influence of transversal forces on deformation were taken into account. The second type of element neglects influence of transversal forces on deformation, concerning assumption that cross section remain plane and orthogonal on the middle line is adopted. A number of numerical examples are calculated by a computer program written in program language C as a proof of accuracy of previously derived theoretical reviews.</p>

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19234号 / 工博第4069号 / 新制||工||1628(附属図書館) / 32233 / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 渡辺 宏, 教授 古賀 毅, 教授 金谷 利治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM