Program Used:Engineer's Studio®

"This bridge has an 85-meter span with an upward lane constructed with a single steel arch girder and a downward lane constructed with a two-span continuous pre-tensioned I-girder plus a single steel arch girder. The single steel arch girder section is an integrated structure for both lanes, while the PC girder section has a separated structure for each lane.To properly assess the seismic performance of the existing bridge and understand the scope of reinforcement required, dynamic analysis was conducted. This involved creating a fiber model to consider the effects of axial force variations on steel members, and developing a nonlinear model for piers connected to the abutment and beams as framed piers. Additionally, the modeling took into account the resistance of the soil behind the abutments, focusing on the surrounding characteristics. As a result, it was found that the shear capacity of the beam members was insufficient, providing fundamental data for the detailed design of future reinforcements.

Program Used:Engineer's Studio®

Experimental results have shown that the failure modes of hollow RC pier sections in existing structures differ from those of solid sections, leading to the limitation of M-φ properties application to "solid sections" as of the H24 specifications. Consequently, there is currently no established verification method to replace M-φ properties for hollow sections. Some commissioning agencies assume that the plane retention assumption is valid by filling hollow sections with air mortar, thus applying M-φ properties even in the plastic region. However, as air mortar cannot be applied to the upper ends of the columns, there is inconsistency in handling the rigidity characteristics of the plasticized upper ends (hollow areas) in in-plane analyses. While 3D FEM analyses are sometimes used, they present issues with increased time and cost.Therefore, this report proposes challenges and solutions for utilizing Engineer's Studio® fiber models as a more simplified verification method.

Program Used:Engineer's Studio®

The M7.6 Noto Peninsula Earthquake of January 1 this year caused extensive damage to various structures. This earthquake marked the first time in Japan that a building collapsed due to pile damage. The cause is believed to be the amplification of building vibrations on soft ground. Many bridges in the affected area are also supported by piles on weak ground. Furthermore, approximately eight months after this earthquake, the Noto Peninsula experienced a compound disaster, with record rainfall leading to flooding, landslides, and extensive road damage.

Program Used:Engineer's Studio®

In constructing a new bridge abutment adjacent to a railway track, excavation was carried out for the pile foundation of the A1 abutment. Steel sheet pile earth-retaining walls were installed, and a multi-stage excavation was conducted with struts. The ground composition includes a 7-meter thick embankment layer at the surface, followed by a 15-meter thick alluvial layer consisting of alternating layers of clayey, sandy, and gravelly soils, and then a diluvial layer. The excavation depth reaches the base of the embankment layer at 7 meters, with two levels of struts. As the railway track center is located just 6 meters from the excavation face, ground deformation due to excavation was a concern. A linear elastic FEM analysis was conducted, with a multi-stage approach to simulate the excavation process. This report summarizes the results of the ground deformation analysis.

Program Used:FEMLEEG®

After replacing the existing RC deck slab of a steel girder bridge, it is common for the dead load of the slab to increase, and live loads have also increased since the bridge was originally built. Therefore, stress checks of the existing steel girder bridge after deck replacement are conducted as part of the project. This analysis involved checking the stress in the steel girders after replacing the deck using a grid analysis method. Since excessive stress was observed in some areas, a linear FEM analysis was additionally conducted using a full model to more accurately represent the actual stress conditions. The analysis was carried out by creating a three-step model for each construction stage and then combining these steps.

Program Used:2D Seepage Flow Analysis(VGFlow®2D)

To evaluate the safety of an irrigation pond embankment against seepage failure, a steady-state analysis was conducted under conditions of full water level and water level drawdown to determine the safety factors against seepage failure and piping. The stratigraphy comprises a clayey soil embankment, with underlying highly weathered limestone at the top, followed by weathered limestone, limestone, and interbedded clayey inflow sediments. The foundation consists of alternating layers of sandstone and shale. Two cases were examined: Case 1, where a seepage boundary is set on the pond side, and Case 2, where the slope on the pond side is covered with an impermeable sheet. Slope stability calculations were performed to determine the safety factor of the slope and assess stability. This report summarizes the results of the seepage flow analysis and slope stability calculations.

Program Used:Engineer's Studio®

This bridge is a three-span continuous non-composite I-girder bridge, constructed in the early Heisei era. It features rigid-frame piers, but due to its mountainous location, a slope perpendicular to the bridge axis results in an irregular two-tiered rigid-frame structure. Additionally, as it is a skew bridge, a 3D model was created to analyze whether it meets Seismic Performance Level 2 during a Level 2 earthquake.

Program Used:Engineer's Studio®

"This bridge is a three-span continuous non-composite I-girder bridge constructed in the early Heisei period. It has framed piers, but due to its location in a mountainous area, there is an irregular two-step framed structure with slopes perpendicular to the bridge axis. Additionally, as it is a skew bridge, a 3D model was created to analyze if it satisfies seismic performance level 2 during a Level 2 earthquake.The results showed damage in the current state analysis, indicating that reinforcement is necessary. Therefore, wrapping reinforcement with carbon fiber sheets was considered, and the reinforcement content needed to satisfy the seismic performance was calculated.

Program Used:Engineer's Studio®

For a reinforced concrete river structure, a structural analysis was conducted using a 3D plate model that accounts for the reduction in compressive strength due to concrete deterioration. This analysis was used to assess the structure's integrity and seismic performance. If the current seismic performance is deemed sufficient, immediate repair or reinforcement may not be necessary. However, by incorporating future projected values of concrete deterioration into the analysis model, it is possible to predict when the structural integrity and seismic performance may no longer meet required standards. This approach helps determine the optimal timing for repairs or reinforcements. Additionally, optimizing the timing for these interventions can enable a more efficient implementation schedule within budget constraints.

Program Used:UC-win/Road、xpswmm
In recent years, as natural disasters have become more severe, frequent, and widespread, there has been a growing need for society as a whole to understand disaster risk and prepare for disasters in advance. As more and more 3D city models across Japan are developed and used in the Project PLATEAU, various disaster-related information is superimposed on the 3D city models to visualize disaster risks in 3D and in chronological order. This makes it easy to understand in an intuitive way, which can lead to improved disaster prevention awareness among residents and the formulation of evacuation plans. Therefore, a digital twin of Tamana City was created by incorporating a 3D city model (CityGML) into the 3D VR space, and a flood simulation was performed based on the 3D city model. The results were reproduced in real time in the 3D VR space, showing disaster risks in an easy-to-understand way. It is also planned to use them for disaster prevention planning and evacuation route determination.

Program Used:Engineer's Studio®、
UC-BRIDGE・3DCAD(Partial Factor Method)
Tenjingawa Bridge (tentative name) is a 7-span continuous double-layer arch RC bridge with a length of 552.0 m. It is located between the Otsu JCT and the Joyo JCT (25 km) of the Shin-Meishin Expressway at the section over the Tenjingawa River, a first-class river flowing through Otsu City, Shiga Prefecture. The lower part is an open spandrel arch, and the upper part uses a solid spandrel arch, which allows a pavement structure similar to that of ordinary embankments. Because this bridge had a structure unprecedented in highway bridges, advanced analysis techniques were required in its design, and UC-BRIDGE and Engineer's Studio® were used for the analysis.