Probabilistic assessment of calculation resistance models of composite section with partial shear interaction

Istraživani su spregnuti nosači u zgradarstvu s djelomičnom posmičnom vezom. Postupak određivanja točne otpornosti presjeka na savijanje takvih spregnutih nosača iterativan je i dugotrajan. Analizirana su četiri različita proračunska modela otpornosti, različitih autora, koji omogućuju neiterativno određivanje otpornosti ovakvih nosača. Laboratorijski utvrđena otpornost poprečnog presjeka na savijanje uspoređena je s otpornostima dobivenim korištenjem različitih modela, nakon čega su računski modeli probabilistički evaluirani. Rezultat ovakve analize je najpouzdaniji neiterativni proračunski model za određivanje otpornosti na savijanje poprečnih presjeka s djelomičnom posmičnom vezom Nadalje, predlaže se novi proračunski model otpornosti. Predloženi model se temelji na linearnom modelu koji se zatim prilagođava najpouzdanijem neiterativnom proračunskom modelu otpornosti. Koeficijent korekcije određuje se na determinističkoj razini, nakon koje se provodi probabilistička analiza novog modela. Rezultat istraživanja je vrlo jednostavan neiterativni model koji daje razinu pouzdanosti u skladu s ciljanom vrijednosti indeksa pouzdanosti.Composite beams in buildings with partial shear connection have been researched. The procedure of determining the exact resistance of such composite beams in bending with partial shear interaction is iterative and tedious. Four different calculation resistance models of various authors for non-iterative determination of such cross-section resistance have been analysed. Bending resistance of cross-section obtained from laboratory tests is compared with the resistance calculated from different models after which the calculation models are probabilistically evaluated. The result is the most certain non-iterative calculation resistance model of cross-section in bending for a beam with partial shear interaction. Furthermore, a new resistance model is proposed. The proposed model is based on a linear model which is then modified according to the most favourable non-iterative calculation resistance model. Correction coefficient is obtained on a deterministic level, after which probabilistic evaluation of the new model is conducted. The result is a very simple non-iterative model with the reliability levels close to the target value of the reliability index

New Connectors for Joining Truss Beams to Vertical Stud Made of Thin-Walled Steel C-Profiles

Predstavljeno je istraživanje koje je provodeno u okviru znanstvenog-razvojnog projekta UNIRI INOVA „Inovativni priključak za spajanje konstrukcijskih elemenata od tankostijenih čeličnih C-profila“. Cilj projekta je pružiti bolje razumijevanje o ponašanju komponenti inovativnog priključka za spajanje elemenata od tankostijenih čeličnih C-profila.The research that was conducted as part of scientific and development project UNIRI INOVA "New connector for joining structural elements made of thin-walled steel C-profiles" was presented. The project goal is to provide better knowledge about the behavior of new connection components for joining elements made of thin-walled steel C-profiles

Investigation of Behaviour of Composite Panel Components With Integrated Steel Core

U radu je predstavljeno istraživanje u okviru znanstvenog projekta ZIP UNIRI „Istraživanje ponašanja komponenti kompozitnog panela s integriranom čeličnom jezgrom“. Cilj znanstvenog projekta je pružiti bolje razumijevanje o ponašanju komponenti inovativnog konstruktivnog panelnog sustava kako bi se istražio potencijal njegove primjene u građevinarstvu.The paper presents research conducted as part of the ZIP UNIRI scientific project “Investigation of the behaviour of composite panel components with integrated steel core”. The aim of the scientific project is to better understand the behaviour of the components of the innovative structural panel system in order to investigate the potential of its application in construction

Probabilistic assessment of calculation resistance models of composite section with partial shear interaction

Istraživani su spregnuti nosači u zgradarstvu s djelomičnom posmičnom vezom. Postupak određivanja točne otpornosti presjeka na savijanje takvih spregnutih nosača iterativan je i dugotrajan. Analizirana su četiri različita proračunska modela otpornosti, različitih autora, koji omogućuju neiterativno određivanje otpornosti ovakvih nosača. Laboratorijski utvrđena otpornost poprečnog presjeka na savijanje uspoređena je s otpornostima dobivenim korištenjem različitih modela, nakon čega su računski modeli probabilistički evaluirani. Rezultat ovakve analize je najpouzdaniji neiterativni proračunski model za određivanje otpornosti na savijanje poprečnih presjeka s djelomičnom posmičnom vezom Nadalje, predlaže se novi proračunski model otpornosti. Predloženi model se temelji na linearnom modelu koji se zatim prilagođava najpouzdanijem neiterativnom proračunskom modelu otpornosti. Koeficijent korekcije određuje se na determinističkoj razini, nakon koje se provodi probabilistička analiza novog modela. Rezultat istraživanja je vrlo jednostavan neiterativni model koji daje razinu pouzdanosti u skladu s ciljanom vrijednosti indeksa pouzdanosti.Composite beams in buildings with partial shear connection have been researched. The procedure of determining the exact resistance of such composite beams in bending with partial shear interaction is iterative and tedious. Four different calculation resistance models of various authors for non-iterative determination of such cross-section resistance have been analysed. Bending resistance of cross-section obtained from laboratory tests is compared with the resistance calculated from different models after which the calculation models are probabilistically evaluated. The result is the most certain non-iterative calculation resistance model of cross-section in bending for a beam with partial shear interaction. Furthermore, a new resistance model is proposed. The proposed model is based on a linear model which is then modified according to the most favourable non-iterative calculation resistance model. Correction coefficient is obtained on a deterministic level, after which probabilistic evaluation of the new model is conducted. The result is a very simple non-iterative model with the reliability levels close to the target value of the reliability index

Experimental Investigation of the CFS-PU Composite Wall Panel under Axial Compression

This study presents an innovative design for a cold-formed steel polyurethane (CFS-PU) composite wall panel, combining a cold-formed steel frame, a polyurethane foam infill, and a gypsum fibreboard sheathing. The foam filling process, in which the foam is injected under pressure, ensures uniform distribution, bonding, and interaction of all panel components. The aim of the study is to evaluate the behaviour of the CFS-PU composite panels and the influence of the PU foam and sheathing on the performance of the CFS frame structure. For this purpose, a comprehensive test programme was conducted with nine full-scale specimens, including four CFS-F specimens without infill and sheathing and five CFS-PU specimens with infill and sheathing on both sides. The study examined various aspects of the specimens, including failure modes, stability, stiffness, load-bearing capacity, and ductility index. By analysing these parameters, valuable insights were gained into the performance characteristics of the composite wall panels. The load-bearing capacity of the CFS-PU test specimens was improved by 2.34 times and the stiffness by 1.47 times compared to the CFS-F test specimens. The positive results highlight the potential of foam and sheathing in improving the axial compression performance of CFS walls

Performance of Novel U-Connector in CFS Truss-to-Column Bolted Connection under Axial Force

This paper presents an experimental and numerical investigation of the tensile and compressive behaviour of a novel U-connector in the cold-formed steel (CFS) truss-to-column connection. Tensile tests were performed on 12 specimens representing the tension chords of the trusses in the connection. The results were used to validate a finite element model. The validated model was then subjected to both compressive and tensile loads, which revealed low stiffness in both the compressive and tensile components of the proposed connection. An optimisation of the geometry by using one long nut instead of two nuts was carried out to improve the behaviour and stiffness of the connection. The optimised results were compared with both experimental and numerical data, and conclusions were drawn regarding the effectiveness of the components in the proposed connection. The use of long-nut optimisation in the tension and compression components of the proposed connection shows a significant increase in load-bearing capacity, which makes it very promising for future applications in CFS truss-to-column connections. However, further validation through experimental testing is required to confirm the effectiveness and reliability of the connection in full-scale structures