Yes / This paper presents test results of eccentrically loaded concrete columns reinforced with steel-fibre-reinforced polymer (FRP) composite bars (SFCBs) subjected to chloride corrosion. The first stage of the experimental work explored the tensile and compressive tests of various reinforcements (SFCBs with different cross section, steel and FRP bars) used in the large reinforced concrete (RC) columns after chloride corrosion with or without sustained stresses. The results showed that the tensile and compressive stress-strain relationships of SFCBs are characterised by stable secondary (post-yield) stiffness. The second stage of the testing investigated the structural performance of RC columns with various amounts and types of reinforcements, slenderness ratio, applied load eccentricity and chloride corrosion rate. The results showed that the effect of reinforcements on eccentric compression behaviour is significant. The deformation and crack width of SFCB RC columns, respectively, decreased by 12.2%~52.6% and 8.5%~71.0%, while the load capacity improved by 0.9%~18.8%, when compared with the corresponding FRP RC columns having the same eccentricity and reinforcement ratio. The use of SFCBs as the reinforcement of RC columns, especially with high reinforcement ratio or SFCBs having high area ratio of inner steel to SFCB, is beneficial to reduce the deflection and crack width as well as improve the bearing capacity utilization coefficients under serviceability limit state.

No / In order to investigate the eccentric compression behaviors of steel-FRP composite bar (SFCB) reinforced concrete (RC) columns subjected to chloride corrosion, the mechanical experiments of chloride corroded SFCBs and SFCBs RC eccentric compression columns were conducted. The effect of reinforcement type and ratio, eccentricity, slenderness, stress level and corrosion duration on bearing capacity, deformation, crack and failure pattern were investigated. The results showed that the strength retention ratio of reinforcement decreases with the increase of corrosion duration, the ultimate strengths of steel rebar, SFCB and FRP rebar decreased by 12.2%, 9.9% and 3.6%, respectively, when compared with those of uncorroded counterparts. With the increase of steel content of reinforcement, the load bearing capacity of eccentric compression RC column increases while the deformation decreases gradually. The load bearing capacity of corroded steel, SFCB and FRP RC columns maximally decreased by 16.6%, 12.4% and 7.2%, respectively, when compared with those of uncorroded counterparts. Based on the simplified materials constitutive relations and reasonable basic assumptions, formulae for discriminate failure mode, moment magnification factor and bearing capacity were developed. The predicted failure pattern, moment magnification factor and bearing capacity are in good agreement with the test results, confirming the validity of the proposed formulae, the results can be used as a reference for engineering application. / High-End Foreign Experts Project of Ministry of Science and Technology, China (G2022014054L), the Natural Science Foundation of Jiangsu Province, China (BK20201436), the Science and Technology Project of Jiangsu Construction System (2018ZD047, 2021ZD06), the Science and Technology Project of Gansu Construction System (JK2021-19), the Opening Foundation of Jiangsu Province Engineering Research Center of PrefabricatedBuilding and Intelligent Construction (2021), the Science and Technology Cooperation Fund Project of Yangzhou City and Yangzhou University (YZ2022194, YZU212105), the Science and Technology Project of Yangzhou Construction System (2022ZD03, 202204), the Nantong Jianghai (226) talents project, the Blue Project Youth Academic Leader of Colleges and Universities in Jiangsu Province (2020).

Deterioration in the mechanical properties of concrete, masonry and steel structures are usually observed under repeated cyclic loading in the inelastic response range. Therefore such a behavior becomes critical when these types of structures are subjected to ground motions with specific characteristics. The objective of this study is to address the influence of degrading behavior on simple systems. The Structural Performance Database on the PEER web site, which contains the results of cyclic, lateral-load tests of reinforced concrete columns, are employed to quantify the degradation characteristics of simple systems by calibrating the selected degrading model parameters for unloading stiffness, strength and pinching of a previously developed hysteresis model. The obtained values of parameters from cyclic test results are compared with the recommended values in literature. In the last part of the study, response of SDOF systems with various degradation characteristics are investigated using a set of seismic excitations recorded during some major earthquakes. The results indicate that when all the degradation components are combined in a structural system, the effect of degradation on response values becomes much more pronounced.

Die vorliegende Arbeit beschäftigt sich mit der Umschnürung von gedrungenen Stahlbetonstützen mittels Kohlefasergelegen. Die durch Epoxidharz mit dem Altbeton verbundenen Kohlefasern (CFK-Umschnürung) bewirken hierbei eine starke Behinderung der Querdehnung des Betons, wodurch dieser in einen dreidimensionalen Spannungszustand versetzt wird. Die Betondruckfestigkeit kann dadurch nachträglich deutlich gesteigert und das Verformungsverhalten positiv beeinflusst werden. Forschungsaufgabe war es, Wissenslücken und aufgeworfene Fragen, die sich aus einer intensiven Literaturrecherche zur Thematik ergaben, zu schließen und einen eigenen Bemessungsansatz zu entwickeln. Hierzu wurden Beton- und Stahlbetondruckglieder mit verschiedenen Abmessungen und Durchmessern sowie unterschiedlichen Längs- und Querbewehrungsgehalten hergestellt. Danach erfolgte die Umschnürung dieser Prüfkörper mit verschiedenen CFK-Materialien in variierenden Dicken und anschließende Bauteiltests in Form von weggesteuerten Druckversuchen. Neben dem Materialverhalten konnten mittels elektrischen Messsystemen, wie z. B. induktiven Wegaufnehmern sowie auf den Prüfkörpern aufgebrachten Dehnungsmessstreifen, auch die Versagenszustände zuverlässig bestimmt werden. Die Auswertung und Interpretation der gewonnenen Daten mündete in empirischen Gleichungen zur Beschreibung der maximalen Druckfestigkeit und Dehnung von CFK-umschnürten Bauteilen aus unbewehrtem oder bewehrtem Beton. Darüber hinaus konnten Aussagen zur tatsächlichen Bruchdehnung der eingesetzten Kohlefasern getroffen und entsprechende Abminderungsfaktoren abgeleitet werden. Unter Berücksichtigung der Datenreihen anderer Forschergruppen wurde die eigene Datenbasis vergrößert und die gewonnenen Erkenntnisse bestätigt. Als Ergebnis steht ein empirischer Bemessungsansatz zur Verfügung, der Bemessungsgleichungen zur Querschnittstragfähigkeit und zugehörigen Dehnung von CFK-umschnürten unbewehrten und bewehrten kreisrunden Stützenquerschnitten bietet. Darüber hinaus können Spannungs-Dehnungs-Beziehungen hergeleitet werden. Durch die Entwicklung von charakteristischen Bemessungsgleichungen gelingt eine einfache Implementierung in bestehende Sicherheitskonzepte. Das entwickelte Modell oder Teile davon eignen sich zur Verwendung in den zur Entstehungszeit der Dissertation vorhandenen Bemessungsvorschriften oder können zu deren Verbesserung herangezogen werden. / This thesis deals with the confinement of short reinforced concrete (RC) columns by carbon-fibre-sheets (CF sheet). In doing so, the connection of concrete surface and CF sheet is enabled by an epoxy resin (CFRP confinement). Thereby, concrete’s lateral expansion is efficiently restricted in cases of imposed axial compressive deformation; therefore, the elastic CFRP resisting response generates an ever increasing lateral compressive stress state on concrete, leading to structural upgrade of the member core to provide a remarkable higher concrete strength and sufficient deformability. Research assignment was to solve open-ended questions and knowledge gaps, which unfolded during an intense literature review, and to present an own proposal of a material model. For this, plain and reinforced concrete columns with different geometrical shape, variable diameter, and different longitudinal and transverse reinforcement elements were produced, and were confined with different CF sheets in variable thickness. Executed deformation controlled compression tests provided investigations concerning the structural behaviour of the test specimens, and electrical measurement techniques such as LVTD and strain gauges enabled a sufficient monitoring of failure modes. The evaluation and interpretation of the received data resulted in empirical equations to predict the ultimate strength and accompanying ultimate axial strain of CFRP confined columns with and without reinforcement. Furthermore, the tests allowed conclusions concerning the rupture strain of the deployed CFRP confinements, and leaded to FRP efficiency factors, capable to predict the actual ultimate strain of the reinforcing fibres. Further data bases, which are available in literature, confirmed the own proposals. As a result, this thesis provides an empirical material model, which deals with proper design equations to predict the load bearing capacity and the deformability of CFRP confined plain and reinforced circular concrete columns. Moreover, it is possible to generate entire stress-strain curves in axial direction. Developed characteristic equations and values allow an easy implementation in existing limit state concepts. The developed model or parts of it are sufficient to be implemented in design guidelines, or they may help to enhance them.

No description available.

Master thesis deals with static analysis of construction of hall type for waste treatment. Thesis includes design and structural assessment of main support elements of construction. This is two-aisled combined skeleton object. The roof system is composed of steel truss structure.

Bakalaurinio baigiamajame darbe projektuojamas vieno aukšto ypatingas statinys – logistikos centras „Logista“. Pastatas projektuojamas Šiaulių miesto pramoniniame rajone, Aerouosto gatvėje. Bendras sklypo plotas 6831,68 m2, užstatymo plotas 1539,49 m2. / In this final work is designed one-story special building – logistic centre „Logista“. Building is designed in industrail district of Šiauliai, Aerouosto street. Overall area is 6831,68 m2, built-up area 1539,49 m2.

The Master´s thesis describes static analysis and design of reinforced concrete prefabricated of the production hall. Entering the work is to verify and dimension elements of structure.

Die vorliegende Arbeit beschäftigt sich mit der Umschnürung von gedrungenen Stahlbetonstützen mittels Kohlefasergelegen. Die durch Epoxidharz mit dem Altbeton verbundenen Kohlefasern (CFK-Umschnürung) bewirken hierbei eine starke Behinderung der Querdehnung des Betons, wodurch dieser in einen dreidimensionalen Spannungszustand versetzt wird. Die Betondruckfestigkeit kann dadurch nachträglich deutlich gesteigert und das Verformungsverhalten positiv beeinflusst werden. Forschungsaufgabe war es, Wissenslücken und aufgeworfene Fragen, die sich aus einer intensiven Literaturrecherche zur Thematik ergaben, zu schließen und einen eigenen Bemessungsansatz zu entwickeln. Hierzu wurden Beton- und Stahlbetondruckglieder mit verschiedenen Abmessungen und Durchmessern sowie unterschiedlichen Längs- und Querbewehrungsgehalten hergestellt. Danach erfolgte die Umschnürung dieser Prüfkörper mit verschiedenen CFK-Materialien in variierenden Dicken und anschließende Bauteiltests in Form von weggesteuerten Druckversuchen. Neben dem Materialverhalten konnten mittels elektrischen Messsystemen, wie z. B. induktiven Wegaufnehmern sowie auf den Prüfkörpern aufgebrachten Dehnungsmessstreifen, auch die Versagenszustände zuverlässig bestimmt werden. Die Auswertung und Interpretation der gewonnenen Daten mündete in empirischen Gleichungen zur Beschreibung der maximalen Druckfestigkeit und Dehnung von CFK-umschnürten Bauteilen aus unbewehrtem oder bewehrtem Beton. Darüber hinaus konnten Aussagen zur tatsächlichen Bruchdehnung der eingesetzten Kohlefasern getroffen und entsprechende Abminderungsfaktoren abgeleitet werden. Unter Berücksichtigung der Datenreihen anderer Forschergruppen wurde die eigene Datenbasis vergrößert und die gewonnenen Erkenntnisse bestätigt. Als Ergebnis steht ein empirischer Bemessungsansatz zur Verfügung, der Bemessungsgleichungen zur Querschnittstragfähigkeit und zugehörigen Dehnung von CFK-umschnürten unbewehrten und bewehrten kreisrunden Stützenquerschnitten bietet. Darüber hinaus können Spannungs-Dehnungs-Beziehungen hergeleitet werden. Durch die Entwicklung von charakteristischen Bemessungsgleichungen gelingt eine einfache Implementierung in bestehende Sicherheitskonzepte. Das entwickelte Modell oder Teile davon eignen sich zur Verwendung in den zur Entstehungszeit der Dissertation vorhandenen Bemessungsvorschriften oder können zu deren Verbesserung herangezogen werden. / This thesis deals with the confinement of short reinforced concrete (RC) columns by carbon-fibre-sheets (CF sheet). In doing so, the connection of concrete surface and CF sheet is enabled by an epoxy resin (CFRP confinement). Thereby, concrete’s lateral expansion is efficiently restricted in cases of imposed axial compressive deformation; therefore, the elastic CFRP resisting response generates an ever increasing lateral compressive stress state on concrete, leading to structural upgrade of the member core to provide a remarkable higher concrete strength and sufficient deformability. Research assignment was to solve open-ended questions and knowledge gaps, which unfolded during an intense literature review, and to present an own proposal of a material model. For this, plain and reinforced concrete columns with different geometrical shape, variable diameter, and different longitudinal and transverse reinforcement elements were produced, and were confined with different CF sheets in variable thickness. Executed deformation controlled compression tests provided investigations concerning the structural behaviour of the test specimens, and electrical measurement techniques such as LVTD and strain gauges enabled a sufficient monitoring of failure modes. The evaluation and interpretation of the received data resulted in empirical equations to predict the ultimate strength and accompanying ultimate axial strain of CFRP confined columns with and without reinforcement. Furthermore, the tests allowed conclusions concerning the rupture strain of the deployed CFRP confinements, and leaded to FRP efficiency factors, capable to predict the actual ultimate strain of the reinforcing fibres. Further data bases, which are available in literature, confirmed the own proposals. As a result, this thesis provides an empirical material model, which deals with proper design equations to predict the load bearing capacity and the deformability of CFRP confined plain and reinforced circular concrete columns. Moreover, it is possible to generate entire stress-strain curves in axial direction. Developed characteristic equations and values allow an easy implementation in existing limit state concepts. The developed model or parts of it are sufficient to be implemented in design guidelines, or they may help to enhance them.

The subject of the diplom thesis is strengthening of building structures. The thesis is focused on strengthening of reinforced concrete compression of rod structures with concrete cover. The thesis consists of three parts. The first one is theoretical treatise on strengthening not only concrete compression of rod structures. The second part describes creating computer program of calculating concrete rod element rectangular overview which is made stronger with concrete cover using method of limit transformation. The third part consists of the static calculation strengthening of the concrete column rectangular overview with using concrete strengthening cover.