Abstract
To investigate the compressive behavior of partially encased recycled aggregate concrete (PERAC) stub columns
after exposed to elevated temperatures, 22 specimens were tested. The maximum temperature suffered, the replacement ratio of
recycled coarse aggregate (RCA), the endurance time and the spacing between links were considered as the main parameters. It
was found that the failure mode of post-heated PERAC columns generally matched that of traditional partially encased
composite (PEC) columns, but the flange of specimens appeared premature buckling after undergoing the temperature of 400°C
and above. Additionally, the ultimate strength and ductility of the specimens deteriorated with the elevated temperatures and
extended heating time. When 400°C<〈T ≤ 600°C, the strength reduction range is the largest, about 11% ~ 17%. The higher the
replacement ratio of RCA, the lower the ultimate strength of specimens. At the temperature of 600°C, the ultimate strength of
specimens with the RCA replacement ratio of 50% and 100% is 0.94 and 0.91 times than that of specimens without RCA,
respectively. But the specimen with 50% replacement ratio of RCA showed the best ductility performance. And the bearing
capacity and ductility of PERAC stub columns were changed for the better due to the application of links. When the RCA
replacement ratio is 100%, the ultimate strength of specimens with the link spacing of 100 mm and 50 mm increased 14% and
25% than that of the specimen without links, respectively. Based on the results above, a formula for calculating the ultimate
strength of PERAC stub columns after exposure to high temperatures was proposed.
Key Words
axial compressive; high temperature; partially encased composite; recycled aggregate concrete
Address
Jiongfeng Liang:Faculty of Civil&Architecture Engineering, East China University of Technology, Nanchang, China
Wanjie Zou:College of Civil and Architecture Engineering, Guangxi University of Science and Technology, Liuzhou, China
Liuhaoxiang Wang:College of Architecture and Civil Engineering, Beijing University of Technology, Beijing, 100124, China
Wei Li:1)College of Civil and Architecture Engineering, Wenzhou University, Wenzhou, China
2)Key Laboratory of Engineering and Technology for Soft Soil Foundation and Tideland Reclamation of Zhejiang Province,
276 Yuanzhong Road, Wenzhou, P.R. China
Abstract
Once the foundation displacement of the transmission tower occurs, additional stress will be generated on the tower
members, which will affect the seismic response of transmission tower-line systems (TTLSs). Furthermore, existing research has
shown that the reciprocating slippage of joints needs to be considered in the seismic analysis. The hysteretic behavior of joints is
obtained by model tests or numerical simulations, which leads to the low modeling efficiency of TTLSs. Therefore, this paper
first utilized numerical simulation and model tests to construct a BP neural network for predicting the skeleton curve of joints,
and then a numerical model for a TTLS considering the bolt slippage was established. Then, the seismic response of the TTLS
under foundation displacement was studied, and the member stress changes and the failed member distribution of the tower were
analyzed. The influence of foundation displacement on the seismic performance were discussed. The results showed that the
trained BP neural network could accurately predict the hysteresis performance of joints. The slippage could offset part of the
additional stress caused by foundation settlement and reduce the stress of some members when the TTLS with foundation
settlement was under earthquakes. The failure members were mainly distributed at the diagonal members of the tower leg
adjacent to the foundation settlement and that of the tower body. To accurately analyze the seismic performance of TTLSs, the
influence of foundation displacement and the joint effect should be considered, and the BP neural network can be used to
improve modeling efficiency.
Key Words
bolt slippage; BP neural network; foundation displacement; seismic response; tower-line system
Address
Jia-Xiang Li:1)School of Resources and Civil Engineering, Northeastern University, Shenyang, Liaoning 110819, China
2)State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, Liaoning 116024, China
Jin-Peng Cheng:School of Resources and Civil Engineering, Northeastern University, Shenyang, Liaoning 110819, China
Zhuo-Qun Zhang:State Grid Economic and Technological Research Institute Co., Ltd., Beijing 102209, China
Chao Zhang:School of Resources and Civil Engineering, Northeastern University, Shenyang, Liaoning 110819, China
Abstract
This paper presents six novel hybrid machine learning (ML) models that combine support vector machines (SVM),
Decision Tree (DT), Random Forest (RF), Gradient Boosting (GB), extreme gradient boosting (XGB), and categorical gradient
boosting (CGB) with the Harris Hawks Optimization (HHO) algorithm. These models, namely HHO-SVM, HHO-DT, HHORF, HHO-GB, HHO-XGB, and HHO-CGB, are designed to predict the ultimate strength of both rectangular and circular
reinforced concrete (RC) columns. The prediction models are established using a comprehensive database consisting of 325
experimental data for rectangular columns and 172 experimental data for circular columns. The ML model hyperparameters are
optimized through a combination of cross-validation technique and the HHO. The performance of the hybrid ML models is
evaluated and compared using various metrics, ultimately identifying the HHO-CGB model as the top-performing model for
predicting the ultimate shear strength of both rectangular and circular RC columns. The mean R-value and mean a20-index are
relatively high, reaching 0.991 and 0.959, respectively, while the mean absolute error and root mean square error are low (10.302
kN and 27.954 kN, respectively). Another comparison is conducted with four existing formulas to further validate the efficiency
of the proposed HHO-CGB model. The Shapely Additive Explanations method is applied to analyze the contribution of each
variable to the output within the HHO-CGB model, providing insights into the local and global influence of variables. The
analysis reveals that the depth of the column, length of the column, and axial loading exert the most significant influence on the
ultimate shear strength of RC columns. A user-friendly graphical interface tool is then developed based on the HHO-CGB to
facilitate practical and cost-effective usage.
Address
Quang-Viet Vu:1)Laboratory for Computational Civil Engineering, Institute for Computational Science and Artificial Intelligence, Van Lang University,
Ho Chi Minh City, Vietnam
2)Faculty of Civil Engineering, School of Technology, Van Lang University, Ho Chi Minh City, Vietnam
Van-Thanh Pham:Faculty of Civil Engineering, Thuyloi University, 175 Tay Son, Dong Da, Hanoi, Vietnam
Dai-Nhan Le:Faculty of Building and Industrial Construction, Hanoi University of Civil Engineering, Hanoi, Vietnam
Zhengyi Kong:Institute for Sustainable Built Environment, Heriot-Watt University, Edinburgh, United Kingdom
George Papazafeiropoulos:Department of Structural Engineering, School of Civil Engineering, National Technical University of Athens, Zografou, Athens 15780, Greece
Viet-Ngoc Pham:Faculty of Civil Engineering, Thuyloi University, 175 Tay Son, Dong Da, Hanoi, Vietnam
Abstract
Grouted sleeve splice (GSS) is an effective type of connection applied in the precast concrete structures as it has the
advantages of rapidly assembly and reliable strength. To decrease the weight and cost of vertical rebar connection in precast
shear walls, a light-weight sleeve is designed according to the thick-cylinder theory. Mechanical behaviour of the light-weighted
GSS is investigated through experimental analysis. Two failure modes, such as rebar fracture failure and rebar pull-out failure,
are found. The load-displacement curves exhibit four different stages: elastic stage, yield stage, strengthening stage, and necking
stage. The bond strength between the rebar and the grout increases gradually from outer position to inner position of the sleeve,
and it reaches the maximum value at the centre of the anchorage length. A finite element model predicting the mechanical
properties of the light-weighted GSS is developed based on the Concrete Damage Plasticity (CDP) model and the Brittle
Cracking (BC) model. The effect of the rebar anchorage length is significant, while the increase of the thickness of sleeve and
the grout strength are not very effective. A model for estimating ultimate load, including factors of inner diameter of sleeves,
anchorage length, and rebar diameter, is proposed. The proposed model shows good agreement with various test data.
Key Words
bond strength; finite element; grouted splice; light-weight sleeve; ultimate load
Address
Quanwei Liu:Department of Civil Engineering, Anhui University of Technology, China
Tao Wu:Department of Civil Engineering, Chang'an University, China
Zhengyi Kong:Institute for Sustainable Buit Environment, Heriot-Watt University, United Kingdom
Xi Liu:Department of Civil Engineering, Chang'an University, China
Ran Chen:Department of Civil Engineering, Chang'an University, China
Kangxiang Hu:Department of Civil Engineering, Anhui University of Technology, China
Tengfei Xiang:Department of Civil Engineering, Anhui University of Technology, China
Yingkang Zhou:Department of Civil Engineering, Anhui University of Technology, China
Abstract
Not all structural columns maintain a vertical orientation. Several contemporary building structures have inclined
columns, introducing distinct challenges, particularly in buckling behavior. This study examines the buckling behavior of
inclined, thin-walled steel bundled columns, differing from typical vertical columns. Using specimens with three tubes welded to
plates linearly aligned at the top and triangularly at the bottom, tests indicated that buckling capacity increases with tube wall
thickness and diameter but decreases with column height. Inclined tubes in bundled columns showed improved buckling
resistance over vertical ones. Results were verified against standard steel design guidelines to assess their predictive accuracy.
Key Words
buckling behavior; bundled column; inclined columns; steel; thin-walled
Address
Moussa Leblouba:Department of Civil & Environmental Engineering, College of Engineering, University of Sharjah, United Arab Emirates
Samer Barakat:Department of Civil & Environmental Engineering, College of Engineering, University of Sharjah, United Arab Emirates
Raghad Awad:Department of Civil & Environmental Engineering, College of Engineering, University of Sharjah, United Arab Emirates
Saif Uddin Al-Khaled:Department of Civil & Environmental Engineering, College of Engineering, University of Sharjah, United Arab Emirates
Abdulrahman Metawa:Department of Civil & Environmental Engineering, College of Engineering, University of Sharjah, United Arab Emirates
Abdul Saboor Karzad:2Department of Civil Engineering, Faculty of Engineering, University of Ottawa, Canada
Abstract
The Caynarachi Bridge is a 130 m long posttensioned steel-concrete composite bridge built in Peru. The structural
performance of this bridge under construction loads is reviewed in this paper using numerical simulation. Hence, a numerical
model using shell finite elements to trace its deformational behavior at service conditions is proposed. The geometry and
boundary conditions of the superstructure are updated according to the construction schedule. Firstly, the adequacy of the
proposed model is validated with the field measurements obtained from the static truck load test. Secondly, the study of other
scenarios less explored in research are performed to investigate the effect of some variables on bridge performance such as time
effects, sequence of execution of concrete slabs and type of supports conditions at the abutments. The obtained results show that
the original sequence of execution of the superstructure better behaves mechanically in relation to the other studied scenarios,
yielding smaller stresses at critical cross sections with staging. It is also demonstrated that an improper slab staging may lead to
more critical stresses at the studied cross sections and that casting the concrete slab at the negative moment regions first can lead
to an optimal design. Also, the long-term displacements can be accurately predicted using an equivalent composite resistance
cross section defined by a steel to concrete modulus ratio equal to three. This article gives some insights into the potential
shortcomings or advantages of the original design through high-fidelity finite element simulations and reinforces the
understating of posttensioned composite bridges with staging
Key Words
composite bridges; construction stage analysis; finite element method
Address
Marcela P. Miranda:Center of Applied Mechanics and Computational (CEMACOM,) Engineering School of Federal University of Rio Grande do Sul,
Av. Osvaldo Aranha 99-3ofloor, 90035-190, Porto Alegre, RS, Brazil
Jorge L. P. Tamayo:Department of Civil Engineering, Engineering School Federal University of Rio Grande do Sul,
Av. Osvaldo Aranha 99-3ofloor, 90035-190, Porto Alegre, RS, Brazil
Inácio B. Morsch:2Department of Civil Engineering, Engineering School Federal University of Rio Grande do Sul,
Av. Osvaldo Aranha 99-3ofloor, 90035-190, Porto Alegre, RS, Brazil
Abstract
The objective of this paper was to discuss the seismic performance of hybrid FRP-steel reinforced concrete shear
wall with replaceable friction dampers at the feet of the wall. The hysteretic characteristics of five wall specimens were studied
by pseudo-static loading tests. The results showed that the damage of the specimens was concentrated on the friction dampers,
and the energy consumption capacity was increased while making up for the defect of low ductility of FRP reinforced wall
specimens. And the repairability of the wall after earthquake was improved. Finally, a calculation method of initial stiffness of
shear wall with replaceable dampers was proposed.
Key Words
energy consumption capacity; hybrid FRP-steel reinforced concrete shear wall; pseudo-static test;
replaceable friction damper; seismic behavior
Address
Shiying Xiao and Mengfu Wang:College of Civil Engineering, Hunan University, Yuelushan, Changsha, Hunan 410082, People's Republic of China
Abstract
In order to make the dynamic analysis and design of improved composite beam with corrugated steel web
(CBGSCC) bridge more efficient and economical, the parametric self-cyclic analysis model (SCAM) was written in Python on
Anaconda platform. The SCAM can call ABAQUS finite element software to realize automatic modeling and dynamic analysis.
For the CBGSCC bridge, parameters were set according to the general value range of CBGSCC bridge parameters in actual
engineering, the SCAM was used to calculate the large sample model generated by parameter coupling, the optimal value range
of each parameter was determined, and the sensitivity of the parameters was analyzed. The number of diaphragms effects
weakly on the dynamic characteristics. The deck thickness has the greatest influence on frequency, which decreases as the deck
thickness increases, and the deck thickness should be 20-25 cm. The vibration frequency increases with the increase of the
bottom plate thickness, the web thickness, and the web height, the bottom plate thickness should be 17-23mm, the web thickness
should be 13-17 mm, and the web height should be 1.65-1.7 5 m. Web inclination and Skew Angle should not exceed 30°C, and
the number of diaphragms should be 3-5 pieces. This method can be used as a new method for structural dynamic analysis, and
the importance degree and optimal value range of each parameter of CBGSCC bridge can be used as a reference in the design
process.
Key Words
composite box girder with steel bottom plate-corrugated web-concrete deck bridge; dynamic characteristic;
large sample parameters; python language; self-circulated analysis model; self-circulated analysis model
Address
Zhongying He:Department of Civil Engineering and Architecture, Henan University, Kaifeng, Henan, 475000, Republic of China
Yifan Song:Department of Civil Engineering and Architecture, Henan University, Kaifeng, Henan, 475000, Republic of China
Genhui Wang:Department of Civil Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu, 730000, Republic of China
Penghui Sun:Department of Civil Engineering and Architecture, Henan University, Kaifeng, Henan, 475000, Republic of China
