Wyniki wyszukiwania - BazTech

1

Właściwości użytkowe ważne w kontekście projektowania murów

Fudalej Piotr, Łaskawiec Katarzyna, Wieczorek Michał

Materiały Budowlane

|

2024

|

nr 4

54--57

2

Badania na ścinanie belek zbrojonych podłużnie i poprzecznie prętami FRP

Szczech Damian, Kotynia Renata

Materiały Budowlane

|

2024

|

nr 4

32--36

PL

W artykule przedstawiono przegląd literatury w dziedzinie badania na ścinanie belek zbrojonych podłużnie i poprzecznie prętami FRP. Przegląd badań obejmuje zestawienie parametrów różnych zmiennych: rodzaju zastosowanego zbrojenia; wysokości użytecznej elementu; szerokości belek; smukłości ścinania; wytrzymałości betonu na ściskanie; stopnia zbrojenia podłużnego i poprzecznego; modułu sprężystości prętów; kształtu strzemion; porównania z elementami zbrojonymi prętami stalowymi, a także schematu statycznego. Na podstawie przeglądu wiedzy zaproponowano program badań własnych.

EN

This article presents a review of research in the field of shear tests of beams with longitudinal and transverse FRP reinforcement. The research review includes a summary of the parameters of various variables: type of reinforcement, depth of the element, width of the beams, shear span to depth ratio, compressive strength of concrete, longitudinal and transverse reinforcement ratio, modulus of elasticity of bars, shape of stirrups, comparison with elements reinforced with steel bars, as well as the static scheme. Based on the foreign studies the own research program has been proposed.

3

Municipal waste management based on geomechanical assessments of the landfill site slope - a case study in southern Poland

Janoszek Tomasz, Nguyen Phu Minh Vuong, Grabowski Jacek

Journal of Sustainable Mining

|

2024

|

Vol. 23, iss. 2

185--198

EN

Over time, municipal waste landfills tend to go higher and become larger. The stability of the municipal landfill slope is one of the basic geotechnical tasks. This task ensures continuous waste deposition on the landfill surface and safety in its surroundings. With the increasing height and volume of the landfill, it is difficult to estimate the available area of the municipal landfill, where more waste can be safely deposited due to a number of variable factors, such as the geotechnical conditions of the municipal landfill, the morphological composition, age, and degree of compaction and decomposition of the deposited waste. This paper presents an attempt to determine the available area of a landfill where municipal waste can be safely deposited for further operation. For this purpose, a numerical slope stability analysis was carried out using the finite difference method code FLAC3D, presenting the actual geomechanical conditions of a landfill located in southern Poland. Based on the numerical results, options for municipal waste storage were presented and discussed. The proposed design chart aims to help landfill owners/managers make an adequate decision in terms of landfill planning and design.

4

Effects of Contamination with Gasoline and Diesel Oil on Shear Strength of Coarse Grained Soil

Brzeziński Bartłomiej, Olchawa Andrzej

Rocznik Ochrona Środowiska

|

2023

|

Tom 25

222--227

EN

The paper presents research results into the influence of motor fuels on the shear strength of coarse-grained soil. The soil was classified following the unified soil classification system PN-EN ISO 14668-1 as saGr. The soil samples were artificially contaminated with three percentage ratios of motor fuels 5, 7.5 and 10% in relation to the dry mass of the soil skeleton. The test results have shown that motor fuel contamination significantly impacts the tested soil's mechanical properties. Increasing the content of impurities causes a significant decrease in shear strength parameters. For soil contaminated with 5%, 7.5% and 10% of motor fuel, i.e. gasoline or diesel, the angle of internal friction decreased by 8%, 15% and 20%, respectively. Along with the impurities increase, the soil's ultimate bearing capacity, calculated following EC-7, showed a dramatic decrease. The decrease was 40%, 57% and 66% respectively.

5

Behavior study of the steel plate girder with a cellular honeycomb web

Ammash Haider K., Shaffaf Noora N.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

|

2023

|

Vol. 32, No. 2

101--116

EN

Based on the experimental test results of the authors, this investigation is concerned with the finite element analysis to examine and compare the load values and failure modes of the authors’ results. This research was conducted using the Abaqus software. The experimental work included the fabrication of twelve plate girders with honeycomb and flat web plate corrugation patterns, which were then tested under a single concentrated load at the midspan. According to the corrugation dimension or outer honeycomb web thickness, the honeycomb steel plate web girder is divided into three groups (60 mm, 80 mm and 100 mm). The specimens also involved plate girders with a flat web. The specimens were created with three lengths (600 mm, 1,200 mm and 1,800 mm). The Abaqus software was used in finite element models to simulate the concentrated load. The numerical results demonstrated that the 60 mm thick honeycomb web provides a greater load-bearing capacity and shear strength than other girders. The 20 mm honeycomb corrugation on the steel plate girder indicates the increased and improved shear resistance. The conclusion was that as the width of the corrugation increased, so did the steel web’s ultimate load and shear strength, resulting in a positive relationship between the critical shear buckling load of the web and the moment of inertia at the strong axis. When the dimension of the corrugation increases, the moment of inertia of the Y axis (Iy) decreases; thus, the plate girder will fail with a less critical buckling load (Pcr). Also, it can be concluded that as the steel plate thickness of the honeycomb web increases, the shear resistance increases as well. However, the spacing between the intermediate stiffener or the horizontal spacing of the web panel can enhance the shear resistance of honeycomb web girder if it was decreased due to increasing the action of tension field force that resists the diagonal tension developed at the web panel by the applied midspan concentrated force.

6

Ocena wpływu ekstremalnych temperatur utwardzania wyrobów do konstrukcyjnego łączenia materiałów na ich wybrane właściwości użytkowe

Wojnowski Damian, Bardan Magdalena

Przegląd Budowlany

|

2023

|

R. 94, nr 7-8

65--69

PL

Celem eksperymentu była ocena wpływu temperatury utwardzania na wybrane właściwości użytkowe wyrobów do łączeń konstrukcyjnych. Do badań wytypowano trzy kleje epoksydowe przeznaczone - w ramach naprawy konstrukcji betonowych - do przyklejania materiałów, takich jak np. maty z włókien węglowych, szklanych i aramidowych. Substraty, z których składają się poszczególne kleje, jak również przygotowane obiekty badawcze, kondycjonowano w warunkach laboratoryjnych oraz ekstremalnych temperaturach utwardzania, wytypowanych do projektu w oparciu o informacje znajdujących się w kartach technicznych wyrobów. Jako temperatury ekstremalne przyjęto maksymalną 35˚C i minimalną 10˚C wartość deklarowaną wspólną dla wytypowanych klejów. Przeprowadzono badania, których wyniki stanowią podstawowe kryterium oceny jakości połączeń klejowych, takie jak: wytrzymałość na ścinanie (przy różnych wartościach kąta nachylenia złącza), wytrzymałość na ściskanie i zginanie. Dodatkowo wykonano badanie przyczepności betonu starego do betonu starego, które pozwoliło określić, jaki wpływ ma temperatura utwardzania na połączenie kleju i betonu. Analiza uzyskanych wyników wykazała wpływ temperatury utwardzania wyrobów do łączeń konstrukcyjnych na ich wybrane właściwości użytkowe. Większy wpływ na obniżenie poziomu uzyskanych parametrów ma spadek temperatury utwardzania klejów do łączenia konstrukcyjnego do 10°C.

EN

The aim of the experiment was to evaluate the influence of the hardening temperature on selected performance properties of products for construction joints. Three epoxy adhesives were selected for the tests, intended - as part of the repair of concrete structures - for gluing materials such as carbon, glass and aramid fiber mats. The substrates, which make up the individual adhesives, as well as the prepared research objects, were conditioned in laboratory conditions and extreme hardening temperatures, selected for the project based on the information contained in the technical data sheets of the products. The maximum 35˚C and minimum 10˚C declared values shared by the selected adhesives were adopted as extreme temperatures. Tests were carried out, the results of which constitute the basic criterion for assessing the quality of adhesive joints, such as: shear strength (at different values of the angle of inclination of the joint), compressive and bending strength. In addition, the adhesion test of the old concrete to the old concrete was performed, which allowed to determine the influence of the hardening temperature on the bonding of the adhesive and concrete. The analysis of the obtained results showed the influence of the hardening temperature of products for construction joints on their selected performance properties. The decrease in the curing temperature of structural adhesives to 10°C has a greater impact on the reduction of the obtained parameters.

7

Wpływ zróżnicowanego składu kompozytu geopolimerowego na adhezję z kompozytem asfaltowym

Granatyr Krzysztof, Bołtryk Michał, Kalinowska-Wichrowska Katarzyna, Szeligowski Paweł

Materiały Budowlane

|

2023

|

nr 5

5--9

PL

W artykule przedstawiono badania wpływu zróżnicowanego składu kompozytu geopolimerowego na adhezję z kompozytem asfaltowym. Zmiennymi w planie eksperymentu były zawartość zaprawy geopolimerowej, stężenie molowe NaOH oraz grubość warstwy ochronnej kompozytu geopolimerowego. Przyjęto stałe warunki dojrzewania. Otrzymane wyniki wskazują na bardzo dobre właściwości kompozytu zespolonego niezależnie od badanych czynników.

EN

The article presents the research on the influence of the variable composition of the geopolymer composite on the adhesion with the asphalt composite. The variables in the experiment plan were the content of the geopolymer mortar, the molar concentration of NaOH and the thickness of the protective layer made of the geopolymer composite. Constant maturation conditions were assumed. The obtained results indicate very good properties of the composite regardless of the tested variable.

8

Eksperymentalna nośność na ścinanie blachownic z falistym środnikiem o różnym typie fali

Śledziewski Krzysztof, Górecki Marcin

Materiały Budowlane

|

2023

|

nr 9

20--23

PL

W artykule przedstawiono wyniki badań laboratoryjnych wykonanych na belkach ze środnikami z blachy fałdowej o różnym profilu sinusoidalnym poddanych działaniu czteropunktowego zginania. Przeprowadzone badania wykazały, że kształt fali ma znaczny wpływ na nośność na ścinanie belek dwuteowych ze środnikiem sinusoidalnym. Uzyskane wyniki odniesiono również do wyznaczonej nośności normowej, która była na niższym poziomie, niż wynika to z badań doświadczalnych.

EN

This paper presents the results of laboratory tests performed on beams with corrugated plate webs of different sinusoidal profiles subjected to four-point bending. The conducted tests showed that the parameters of the waveform have a significant effect on the shear strength of I-beams with sinusoidal webs. The obtained results were also related to the determined norm load capacities, which were at a lower level than the experimental results.

9

Shear Strength of Soil-Root Layer Formed on Degraded Soil Supplemented with New Zeolite Substrate

Chomczyńska Mariola, Franus Małgorzata, Żukowska Grażyna

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 7

128--134

EN

The aim of the study was to determine the shear strength of the soil-root layer obtained as a result of growth of cocksfoot (Dactylis glomerata L.) on degraded soil enriched with the addition of a new zeolite substrate Z-ion. Measurement of shear strength for soil-root layers formed as a result of growth of a grass species (on degraded soil alone and on degraded soil with added Z-ion) was performed in a direct shear apparatus. The measurement results allowed determining parameters of equations describing the dependence of shear strength of studied soil-root layers on normal stress e.g. cohesion and internal friction coefficient. Under the experimental conditions, application of 1% v/v substrate addition to degraded soil induced development of cocksfoot root system which resulted in the significantly increased cohesion of soil-root layer (by 30%) as compared to that formed on degraded soil alone. The enhanced cohesion of the soil-root layer formed on soil enriched with Z-ion resulted in its significantly increased shear strength as compared to that of soil-root layer obtained on soil alone. Further research using higher doses of the Z-ion substrate (greater than 1% v/v) is needed to obtain the information at what dose ranges of the substrate one can expect even more intensive development of plant root systems and, consequently, further significant improvement in the shear strength of the soil-root layers.

10

Shear strength characteristics of weathered jointed Kenny Hill interbedded formation for cylindrical specimen under direct shear test

Abbas Hasan Ali, Mohamed Zainab, Taher Muntadher J., Kudus Sakhiah Abdul, Salman Manaf Raid, Ghaltan Hasanain Muhammad

International Journal of Applied Mechanics and Engineering

|

2023

|

Vol. 28, no. 2

1--12

EN

The sliding failures commonly occur in interbedded formations along the weakness plane of the bedding plane a sedimentary rock or the joint interface. Therefore, studying the shear strength characteristics at the bedding plane or interface is crucial for evaluating the expected failure plane. In this study, the shear strength characteristics of planar jointed Kenny Hill shale, sandstone, and shale-sandstone specimens were investigated using the direct shear box method. The results reveal that the friction angle values for the planar sandstone, shale-sandstone, and shale are 31.28°, 21.1°, and 19.34°, respectively. These findings, combined with the shear stress-strain behavior, suggest that the interface (shale-sandstone) is primarily influenced by the shale characteristics rather than the sandstone characteristics. Hence, it is important to consider failure along the interface when analyzing critical conditions, particularly in slope failure scenarios.

11

Laboratory tests of solid and hollow concrete beams made with glass waste

Alharishawi Salam Salman Chiad, Rajaa Nagham, Jabur Aqeel Raheem

Archives of Civil Engineering

|

2023

|

Vol. 69, nr 4

5--20

EN

The application of used glazed waste in concrete production can improve the performance of the structure of the building. Flexural and shear behavior and action of reinforced Hollow Glass Concrete Beams (HGCB) and Solid Glass Concrete Beams (SGCB) made with glass waste under a two-point load are studied in this paper. In this work, 6 reinforced concrete solid and hollow beams were tested under a four-point bending test to evaluate and calculate the flexural behavior of SGCB and HGCB. For that purpose, Beams were prepared with 1000 mm length, 230 mm height, and 120 mm. All beams were divided into groups and named according to the space stirrups steel bar. The experimental work investigates five main variables which are: first: the comparison between SGCB and HGCB with the concrete beams made with glass waste (Glass Concrete Beam GCB), second: comparison between Solid Concrete Beams for Normal Concrete Beams (NCB), and GCB, three: comparison between Hollow Concrete Beams for NCB and GCB, four: the comparison between HGCB and HCB, last: the comparison between SGCB and SCB. The test results indicated that GCB was offered higher strength than NCB, but the load-slip behavior of all specimens is similar for both types of concretes, and the bond strength is not influenced by steel specimens. Furthermore, the results of this study indicated that the contribution of GCB to the load is indicated to be considerable. The results indicate that the hollow opening affected the ultimate load capacity and deflection of HGCB.

12

Cyclic response and shear mechanisms of RC short walls strengthened with engineered cementitious composites thin layers

Zhang Yangxi, Zhang Shijun, Li Tong, Deng Mingke

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 3

art. no. e148, 2023

EN

This paper investigates the effectiveness of engineering cementitious composites (ECC) thin layers for seismic strengthening of reinforced concrete (RC) short walls with high axial load ratios. Three RC short walls with an aspect ratio of 1.1 were tested under cyclic loading: one control wall and two ECC strengthened walls, adopting two different strengthening layer schemes. The results showed that the failure mode, damage tolerance, lateral stiffness, shear strength, and energy dissipation of the strengthened walls were improved to certain extents. The mesh grid ECC layer was proved an effective and applicable technique, the shear strength and energy dissipation of the corresponding strengthened wall were improved by 37.2% and 33.5%, respectively, and the addition of mesh grid and tie bars in the ECC layer prevented the debonding failure at the ECC/concrete interface. Besides, the shear resistance mechanisms of the test specimens were idealized by the strut-and-tie model, the contribution of cracked ECC tensile strength to shear was considered in the horizontal and vertical mechanisms. The predicted shear strengths of the RC walls agreed well with the test values.

13

Unsaturated soil properties of MICP treated granitic residual soil of Shantou region of China

Hao Li, Lin Peng, Garg Ankit

Acta Geophysica

|

2023

|

Vol. 71, no. 4

1885--1894

EN

Unsaturated soil properties such as soil–water characteristic curve (SWCC) and shear strength are required for seepage and stability flow analyses in various geo-engineering infrastructures. Microbial-induced calcite precipitation (MICP) has been recently adopted for enhancing strength of soils however, with rare focus on improvement in unsaturated soil properties of granitic residual soil. It is known that granite residual soil exhibits unique disintegration properties upon interaction with water. The objective of this study is to investigate the unsaturated properties under different vertical stresses (0, 100, 200 and 300 kPa) for MICP treated granitic residual soils. Further, microstructural characterization of MICP treated soil was conducted to analyse its water retention and shear strength, so as to provide theoretical basis for engineering application of MICP in strengthening granite residual soil. Pressure plate apparatus and FDJ-20 quadruple shear strength apparatus were utilized to obtain SWCCs and shear strength, respectively. Based on the result, it can be concluded that the treatment by MICP is found to enhance the air entry value of granitic residual soil. In addition, MICP treated soils possess higher water content than untreated soil at near-saturated condition. This is due to calcite precipitation on surface of grains and carbonate formation at contact points, which in turn reduces void ratio. However, the difference in water retention reduces with an increase in suction and also confining stress. It is possibly due to breakage of carbonate bonds at contact points at higher stresses. After five times grouting, the effective cohesion, internal friction angle and matric suction angle is found to increase very significantly.

14

The influence of the manufacturing method on the mechanical properties of the honeycomb core sandwich composite

Janiszewski Jacek, Przybyłek Paweł, Bieńczak Rafał, Komorek Łukasz, Schwarzenberg Miłosz

Technologia i Automatyzacja Montażu

|

2022

|

nr 4

20--33

EN

Reducing weight and fuel consumption is one of the main goals of modern aeronautical engineering. The most common materials to achieve this goal are composite layered materials, including the sandwich ones. High strength, stiffness and low density have made sandwich composites one of the fundamental materials of the aerospace industry. Sandwich-structured composites can be manufactured with a variety of methods, differing primarily in the manufacturing time, which translates into an overall cost of making a composite component. The research focused on three methods of manufacturing sandwich composite materials with a honeycomb core, differing in the number of operations, during which it was possible to obtain a finished composite panel (single-phase, two-phase and three-phase methods). The authors manufactured and examined composites with a honeycomb cover and two composite glass fibre-reinforced covers. The composites were made by means of the vacuum bag method. As a result of the conducted study, it was found that composites manufactured with the single-phase method have the shortest manufacture time as well as the lowest material consumption, however their strength properties are the lowest. The two-phase method requires a longer manufacture time and more material consumption, however it makes it possible to obtain a composite with higher strength compared with the single-phase method. The three-phase method has the longest composite manufacture time and the highest material consumption.

PL

Zmniejszenie masy i zużycia paliwa jest jednym z głównych celów współczesnej inżynierii lotniczej. Najpopularniejsze materiały, które pozwalają osiągnąć ten cel, to materiały kompozytowe warstwowe w tym przekładkowe. Wysoka wytrzymałość, sztywność i niska gęstość, sprawiły, że kompozyty przekładkowe stały się jednym z podstawowych materiałów przemysłu lotniczego. Kompozyty przekładkowe z wypełniaczem strukturalnym mogą być wytwarzane różnymi metodami, różniącymi się przede wszystkim czasem wytwarzania, co przekłada się na ogólny koszt wykonania elementu kompozytowego. W badaniach przeanalizowano trzy metody wytwarzania materiałów kompozytowych przekładkowych w wypełniaczem ulowym różniące się liczbą operacji podczas których uzyskano gotową płytę kompozytową (metoda jednofazowa, dwufazowa i trójfazowa). Wytworzono i badano kompozyty zbudowane z rdzenia ulowego oraz dwóch kompozytowych okładek wzmacnianych włóknami szklanymi. Kompozyty wykonano metodą worka próżniowego. W efekcie przeprowadzonych badań stwierdzono, że kompozyty wytworzone metodą jednofazową cechują się najkrótszym czasem produkcji jak i najmniejszym zużyciem materiałów, ale ich właściwości wytrzymałościowe są najniższe. Dwufazowa metoda wymaga dłuższego czasu produkcji i większego zużycia materiałów, natomiast pozwala uzyskać kompozyt o większej wytrzymałości w porównaniu do metody jednofazowej. Trójfazowa metoda cechuje się najdłuższym czasem wykonania kompozytu i największym zużyciem materiałów.

15

Effect of overlap length on the strength of adhesive joints of steel sheets

Doluk Elżbieta, Rudawska Anna, Miturska-Barańska Izabela, Ogrodniczek Jacek

Technologia i Automatyzacja Montażu

|

2022

|

nr 4

3--6

EN

The study evaluates the shear strength of the single-lap adhesive joints made of C45 carbon steel. The influence of the overlap length on the shear strength of the adhesive joint was tested. The elongation of the samples was also tested. Before the bonding process, the samples were treated with P180 abrasive paper and degreased. The adhesive joints were made using the Epidian 53/Z1/100:10 adhesive composition. The strength tests were carried out on a Zwick/Roell Z150 testing machine. The maximum value of the shear strength was obtained for the lap Lz1 = 13 mm and the minimum for Lz4 = 19 mm.

PL

W pracy dokonano oceny wpływu długości zakładki na wytrzymałość na ścinanie jednozakładkowych połączeń klejonych wykonanych ze stali węglowej C45. Podczas eksperymentu zbadano także wydłużenie próbek. Przed rozpoczęciem procesu klejenia próbki zostały obrobione papierem ściernym P180 i odtłuszczone. Połączenia klejowe wykonano przy użyciu kompozycji klejowej Epidian 53/Z1/100:10. Badania wytrzymałościowe przeprowadzono na maszynie wytrzymałościowej Zwick/Roell Z150. Maksymalną wartość wytrzymałości na ścinanie uzyskano dla długości zakładki Lz1 = 13 mm, a minimalną dla Lz4 = 19 mm.

16

Analiza pracy poprzecznej łączników prętów jako przykład działań B+R w nowoczesnej prefabrykacji betonowej

Surma Mateusz, Wojciechowski Szymon

Materiały Budowlane

|

2022

|

nr 3

28--29

17

Characterisation of spoil materials to develop an equivalent spoil material for physical model tests

Garala Thejesh Kumar, Cui Ge, Kantesaria Naman, Heron Charles M., Marshall Alec M., Žižka Lukáš

Górnictwo Odkrywkowe

|

2022

|

R. 63, nr 4

23--29

EN

The engineering behaviour of spoil (overburden) needs to be explored either to understand the stability of reservoir slopes under various geological and climatic conditions or for the effective utilisation of reclaimed mines for sustainable infrastructure (e.g., onshore wind turbines). The spoil material is usually considered as highly heterogeneous, and samples collected from the same site can exhibit widely varying characteristics. In this study, spoil material from a mine site in the Czech Republic is characterised using in-situ field tests and laboratory tests. Cone penetration tests were performed in the field and sample cores were collected for laboratory testing. In the laboratory, the index and engineering characteristics of the spoil were evaluated. Given the measured characteristics and behaviour of the field spoil, an equivalent spoil is proposed to perform physical modelling tests using geotechnical centrifuge. This enables simulation of the field spoil behaviour in controlled centrifuge testing, from which other aspects of spoil (e.g. stability of spoil slopes, spoil-structure interaction) can be investigated.

PL

Zachowanie zwałowisk pogórniczych (nadkładu) pod względem inżynieryjnym powinno zostać zbadane w celu określenia stabilności zboczy zbiorników poeksploatacyjnych w różnych warunkach geologicznych i klimatycznych lub w celu efektywnego wykorzystania rekultywowanych kopalń do budowy zrównoważonej infrastruktury (np. lądowych turbin wiatrowych). Materiał zwałowisk pogórniczych jest zwykle uważany za wysoce niejednorodny, a próbki pobrane z tego samego miejsca mogą wykazywać bardzo różne właściwości. W niniejszej pracy, materiał odpadowy z czeskiej kopalni został scharakteryzowany przy użyciu badań terenowych i laboratoryjnych in-situ. W terenie przeprowadzono sondowania CPT, a do badań laboratoryjnych pobrano próbki rdzeniowe. W laboratorium oceniono właściwości indeksowe i inżynieryjne materiału. Biorąc pod uwagę zmierzone cechy i zachowanie się materiału pogórniczego, zaproponowano materiał równoważny do wykonania modelowania fizycznego z wykorzystaniem wirówki geotechnicznej. Umożliwia to symulację zachowania się materiału w kontrolowanych badaniach wirówkowych, na podstawie których można badać inne cechy materiałów pogórniczych (np. stabilność skarp zwałowiska, interakcje zwałowisko-konstrukcja budowlana).

18

Experimental study on shear mechanical properties of cement mortar specimen with through-step joints under direct shear

Xiong Liangxiao, Chen Haijun, Guo Haogang, Mei Songhua, Xu Zhongyuan, Liu Bin

Archives of Civil Engineering

|

2022

|

Vol. 68, nr 4

45--61

EN

In this study, direct shear tests were carried out on cement mortar specimens with single-ladder, single-rectangular, and double-rectangular step joints. Consequently, the shear strength, and crack shape of specimens with these through-step joints were analyzed, for understanding the influence of the through-step joint’s shape on the direct shear mechanical properties. The results of the investigation are as follows: (1) Under the same normal stress, any increases in the height h of the step joint causes an initial-increase-decrease in the shear strengths of specimens with single-ladder and double-rectangular step joints, causing a type-W variation pattern for the specimens with single-rectangular step joint. More essentially, when normal stress and h are constant, the shear strength of specimens with a single-ladder step joint is the greatest, followed by specimens with a double-rectangular step joint, and then specimens with a single-rectangular step joint is the least. (2) Furthermore, given a small h and low normal stress, specimen with a single-ladder step joint mainly experiences shear failure, whereas specimens with single-rectangular and double-rectangular step joints mainly generate extrusion milling in the step joints.

19

Soft computing approaches for comparative prediction of ram tensile and shear strength in aluminium–stainless steel explosive cladding

Saravanan S., Gajalakshmi K.

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 1

art. no. e42, 2022

EN

This study deals with the application of soft computing techniques viz., response surface methodology, artificial neural network, radial basis function network and support vector regression in analyzing and predicting the ram tensile and shear strengths of aluminium 5052–stainless steel 316 explosive clads, having different interlayer. 60 explosive cladding experiments were conducted, based on central composite design of experiments, by varying the process parameters viz., loading ratio (mass of the explosive/mass of the flyer plate: 0.6–1.0), distance of separation (6–10 mm), preset angle (6°–8°) and interlayer (aluminium 1100/pure copper/stainless steel 304). The responses viz., ram tensile and shear strengths obtained from 90% of the experiments and trial experiments are used for training artificial neural network, radial basis function network and support vector regression in a Matlab environment, altering training algorithms and number of neurons in the hidden layer. The remaining 10% of the experimental outcome is used for testing the developed models. Likewise in RSM, regression equations are generated for the responses, based on analysis of variance. All the four models are capable of predicting the ram tensile and shear strength effectively, as the average percentage deviation with the experimental outcome are less than 10%. Of the three models, artificial neural network model predicts the ram tensile strength and shear strength in a better manner.

20

Nonlinear finite element analysis and parametric study of executable RCS connections

Doost Rooholah Bakhtiari, Sadraie Hamid, Khaloo Alireza, Badarloo Baitollah

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 4

art. no. e204, 2022

EN

This paper compares the results of a nonlinear finite element analysis (FEA) of an internal hybrid steel beam to RC column connections with those of the experiment on a half-scale. This study used extended face bearing plates (EFBP) embedded in the panel zone (PZ) to make prefabricated RC column to steel beam connections (PRCS). Steel beam flanges were made to be stronger than scaled sections to transfer more force to the PZ. Nonlinear FEA was performed with ABAQUS software to evaluate the connections under unidirectional loading. Failure mode, connection stiffness, and PZ shear strength determined by nonlinear FEA matched well with the experimental findings. PRCS1 model was used to evaluate the number of PZ stirrups, axial load on the column, width and height of EFBP, and height of stiffener connected to the beam flange. PZ shear strength and stiffness were significantly improved by increasing EFBP width. Increasing the height of EFBP only with increasing the height of the stiffener can increase the shear strength of the PZ. Increasing the axial load of the column had a significant effect on increasing the shear strength of the PZ. PZ shear strength of the PRCS4 with cover plates (CP) was also assessed by developing its numerical model and strengthening the beams and columns. The presence of CP in the sample without a steel web panel (SWP) illustrated a significant effect compared to the sample with SWP. Based on the performance of the CP in different PZ forms, the formulation was developed to determine the shear strength of CP.