Abstract:Based on the 170 m span network hanger tied-arch bridge of the Guangming Road Guohe Bridge in Bozhou city, structural design and mechanical characteristic analysis are carried out in this study to address the problems associated with traditional vertical hangers in medium-to-large span tied-arch bridges, namely, their susceptibility to slackness, insufficient stiffness, and inadequate stability. The main bridge is a single-span 170 m network hanger tied-arch bridge. The main girder is a double-box steel–concrete composite girder, and the arch rib is an octagonal steel box section without transverse bracing. The hangers are arranged in a crossed network pattern, and the substructure adopts a friction pendulum seismic isolation system. Static, stability, and seismic calculations are performed using the finite element method. The results show that the network hangers can significantly improve the internal force distribution of the main girder and arch rib, reducing both bending moments and deflections. The structural stiffness and stability satisfy the code requirements. The seismic isolation design effectively reduces the seismic response of the piers, and the seismic performance meets the relevant standards. This bridge type demonstrates good technical feasibility and economic rationality for wide urban bridges with spans of 150–200 m and can serve as a reference for similar projects.

Abstract:This paper presents Goliath footbridge, a full-scale 6 m span segmental 3D-printed concrete footbridge activated by post-tensioning, describing the end-to-end process from design and fabrication to transport, assembly, and structural activation. This structure represents the demonstrator of a research project that was conceived as an end-to-end demonstrator integrating material development, digital design, additive manufacturing, and site erection. The printable mortar was previously characterized through rheological and mechanical tests to verify extrusion performance, buildability, and strength development. The structural geometry was obtained through topology optimization under self-weight and pedestrian service loads, aiming to maximize stiffness and reducing material consumption. The resulting solution provided an efficient lightweight configuration adapted to additive manufacturing. After production, the segments were transported to site, rotated into their final position, assembled on temporary supports, aligned through the dry-joint system, and sequentially activated by post-tensioning. The demonstrator confirmed the technical feasibility of combining topology optimization, modular 3D concrete printing, dry-joint assembly, and post-tensioning for pedestrian bridge applications. It also highlighted practical challenges related to dimensional tolerances, local stress concentrations, cracking sensitivity, and durability of joints and anchorage zones. The study provides a practical proof of concept for future scalable 3D-printed concrete bridge construction.

Abstract:To achieve a graded seismic protection objective, namely, no damage under minor earthquakes, repairable damage under moderate earthquakes, and replaceable damage under major earthquakes, a novel rocking bridge system based on shape memory alloy (SMA) ring springs is proposed in this study. A constitutive model of the SMA ring springs is first developed and implemented in open-source finite element software OpenSees. An iterative design procedure for rocking piers is subsequently proposed, in which the slip ratio is adopted as an optimization index for the geometric configuration of the rocking piers. A typical bridge is then selected as a case study example. Finite element models of both a conventional bridge and an engineered cementitious composite (ECC) rocking bridge are subsequently established in OpenSees, and the seismic fragility of the two bridge systems is analyzed. The results indicate that the self-locking mechanism of the SMA ring springs effectively controls the rocking amplitude of the piers, thereby ensuring safe and reliable performance. Compared with conventional bridges, rocking bridges exhibit superior seismic performance and lower seismic fragility.

Abstract:As a core node project of Shenzhen""s "Mountain-Sea-City Connectivity Plan," Kunpeng Trail Bridge No. 3 is located in Qingshuihe Subdistrict, Luohu District. The bridge represents an innovative approach to enhancing ecological connectivity in a high-density urban environment. It adopts a cable-assisted continuous steel truss structure that spans Qingshuihe 3rd Road and Metro Lines 14 and 17. By connecting the western and eastern Maling areas of Honggang Park, the bridge effectively mitigates ecological fragmentation caused by transportation infrastructure barriers. This paper systematically presents the design concepts and key technological innovations associated with the bridge, including its overall layout, structural system, stay cables and anchorage systems, human-induced vibration control, ecological protection and durability measures, and incremental launching construction methods. The study provides valuable technical references for the design and construction of similar long-span ecological corridor bridges.

Abstract:To determine the ultimate bearing capacity of the anchorage zone in a long-span cable-stayed bridge, a typical segment of the anchorage zone was selected for horizontal force mechanism analysis and model loading test, and its load-carrying behavior and deformation characteristics were subsequently analyzed. Results show that under the action of horizontal cable force, the bending moment is relatively large at the outer face of the end tower wall and inner face of the side tower wall, and the chamfer between the side and end walls becomes a critical section because of the combined action of tension, shear and bending. The failure mode is primarily concrete cracking: cracks appear in the end tower wall at 0.15P and penetrate the full height of the segment at 0.25P, while full-depth vertical cracks appear in the side tower wall at 0.20P. The horizontal load of the segmental mode increases nonlinearly with the deformation of the tower wall, and the ultimate bearing capacity reaches 329.70 kN, approximately 0.48P, indicating that the concrete tower wall alone cannot sustain the enormous horizontal cable force. Compared with the side tower wall, the concrete of the end tower wall is more sensitive to the horizontal cable force load. As the horizontal load increases, the load carried by the concrete is gradually transferred to the reinforcement because of the tensile cracking of the tower wall.

Abstract:With the innovation in suspension bridge structures and continuous breakthroughs in spans, greater requirements have been placed on the load capacity and intelligence level of the core equipment for large-span main girder erection—cable-mounted cranes. Traditional cable-mounted cranes suffer from insufficient overall load capacity and relatively low intelligence in the lifting process, leading to low construction efficiency and prominent safety risks. Taking the Wenzhou Oujiang North Estuary Bridge as the research and development background and through structural integration and technological innovation, a 1000-ton cable-mounted crane has achieved automatic clamp crossing, self-adaptive traction angle adjustment during travel, intelligent leveling during lifting, and remote smart operation and maintenance. This crane effectively reduces safety risks caused by human operational errors and improves the overall safety factor. This paper systematically elaborates on the structural assembly, key technological innovations, and main technical parameters of the 1000-ton cable-mounted crane, providing practical and feasible technical solutions and a theoretical basis for enhancing the safety performance and smart operation and maintenance capabilities of cable-mounted cranes.

Abstract:With the increase in the service life of domestic infrastructure, the bridge approach bump formation has become increasingly common. This paper discusses the causes of bridge approach bump formation, which is primarily attributed to the differential settlement between rigid abutment foundations and flexible embankment foundations. This paper also provides a review of factors contributing to the formation of bumps, such as the cracking of approach slabs and soil erosion behind abutments. A prestressed UHPC (ultrahigh performance concrete) approach slab is proposed, and its structural performance is evaluated through finite element analysis, verifying the load-bearing capacity of this new type of approach slab. The novel prestressed approach slab exhibits excellent crack resistance, effectively reducing soil erosion behind abutments and mitigating uneven settlement of foundations near bridge abutments, thereby alleviating the problem of bridge approach bump formation. This study on prestressed approach slabs provides a theoretical basis for slab design and offers a valuable reference for mitigating the formation of bridge approach bumps.