Assessment of Provisions for Load Rating Gusset Plates in Steel Truss Bridges

2021 ◽  
pp. 036119812110312
Author(s):  
Chan Yang ◽  
Peng Lou ◽  
Hani Nassif
Keyword(s):  
Evaluation Method ◽  
State Agencies ◽  
Load Rating ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Truss Bridges ◽  
Federal Highway ◽  
Truss Bridge ◽  
Steel Truss Bridges ◽  
Work Done

Many states have load rated their truss bridge gusset plates following the guidelines published in 2009 by the Federal Highway Administration in response to the catastrophic failure of the I-35W Bridge. As the Manual of Bridge Evaluation released new load rating provisions after 2014, the urgency in adopting and applying these mandated provisions became a pending burden for state agencies requiring extensive work to update the ratings of gusset plates. Moreover, this paper argues that the current states’ load rating practices do not involve the rating for the welded gusset plate owing to the lack of established provisions. In addition, the gusset plate with no plans also poses particular challenges for the state agencies. To provide state agencies with better insights on the load rating approach of gusset plates, this paper presents a study that carefully reviewed the states’ current practices and load rating provisions. The results of the study indicate the necessity of adopting the new provisions, as the former load rating methodology exhibited inaccurate results in some cases. Additionally, this paper reviews extensive work done for welded connections and proposes a load rating guidance for welded gusset plates. To deliver better interpretations, a case study is provided for the welded gusset plates. This paper also reviews the evaluation method for deteriorations and staggered bolt patterns with relevant case studies. Lastly, the paper provides guidance on estimating the unknown bolt strength as well as weld metal strength for the gusset plate.

INFLUENCE OF MEMBER CONNECTION MODELING FOR REDUNDANCY ANALYSIS OF TRUSS BRIDGES

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Keiji Tajima ◽  
Naoyuki Oka ◽  
Kazuaki Uchiyama ◽  
Toshihiko Aso
Keyword(s):  
Redundancy Analysis ◽  
Correct Prediction ◽  
Analysis Model ◽  
Damage State ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Truss Bridges ◽  
Bridge Model ◽  
Truss Bridge ◽  
Model C

To assess critical state of bridges, after-fracture-redundancy plays an important role. Therefore, it is necessary to make a correct prediction of redundancy. However, redundancy from numerical analysis is strongly influenced by various analytical conditions. This study aimed to clarify the influence of member connection modeling and shape of gusset plates on redundancy analysis of truss bridges. Redundancy were computed for three types of analysis model of truss bridge. Model A was a frame model of truss bridge, frame members were connected to each other rigidly as it is. On the other hand, in Model B and Model C, members were connected via gusset plates modeled by shell elements. Gusset plates in model B were rectangle and these of model C had curved shape. Using these three models, redundancies under different analytical condition and different gusset plate shape were compared. From the results of calculation, it was found that bending moment on truss members were strongly influenced by difference of member connection modeling. Computed results also indicated that the influence appears more strongly in damage state than normal state (non-damage state). This result suggested the necessity of accurate modeling of member connection. Furthermore, it was indicated that the redundancy of truss bridges could be improved by change in shape of gusset plates.

The monitoring of temperature differences between steel truss members in long-span truss bridges compared with bridge design codes

2018 ◽  
Vol 22 (6) ◽  
pp. 1453-1466 ◽  
Author(s):  
Gaoxin Wang ◽  
Youliang Ding ◽  
Xingwang Liu
Keyword(s):  
Evaluation Method ◽  
Thermal Action ◽  
Transfer Characteristic ◽  
Primary Concern ◽  
Truss Bridges ◽  
Long Span ◽  
Steel Material ◽  
Steel Truss ◽  
Bridge Structures ◽  
Steel Truss Bridges

The temperature differences in bridge structures have been one primary concern for bridge engineers and researchers. In the traditional view, the temperature differences between steel truss members are treated as uniform because of the good heat transfer characteristic of steel material and the shading effect of deck coverage. However, for some steel truss bridges, some truss members are directly exposed to solar radiation, while some other truss members are totally shaded by steel decks, which may cause obvious temperature differences between them, so it is reasonable to doubt the correctness of uniform temperature existing between steel truss members. In this research, the temperature differences between steel truss members in two long-span truss bridges are analyzed using long-term temperature field data, and after analysis, the temperature differences which contain obvious positive or negative values are made clear. Furthermore, the evaluation method of temperature differences in bridge service life for thermal action design is put forward together with the determination method of probability density function, and the evaluated temperature differences are further obtained after probability statistics analysis. Finally, the evaluated temperature differences are classified by sun radiation and steel deck coverage, and then compared with the specified values in the three specifications. The research results can provide important reference for current specifications and structural design, especially for steel truss bridges.

scholarly journals Damage Diagnosis of Steel Truss Bridges under Varying Environmental And Loading Conditions

2019 ◽  
Vol 24 (No 1) ◽  
pp. 56-67
Author(s):  
Kundan Kumar ◽  
Prabir Kumar Biswas ◽  
Nirjhar Dhang
Keyword(s):  
Damage Detection ◽  
Damage Index ◽  
Loading Conditions ◽  
Damage Diagnosis ◽  
Truss Bridges ◽  
Vibration Data ◽  
Damage Location ◽  
Steel Truss ◽  
Truss Bridge ◽  
Steel Truss Bridges

In this paper, we propose a damage detection and localization algorithm for steel truss bridges using a data-driven approach under varying environmental and loading conditions. A typical steel truss bridge is simulated in ANSYS for data generation. Damage is introduced by reducing the stiffness of one or more members of the truss bridge. The simulated acceleration time-history signals are used for the purpose of damage diagnosis purpose. Vibration data collected from healthy bridges are processed through principal component analysis (PCA) to find the reduced size weighted feature vectors in model space. Unknown test vibration data (healthy or damaged) finds the closest match of its reduced size model from the training database containing only healthy vibration data. The residual error between the spread of closest healthy vibration data and unknown test vibration data is processed to determine damage location and severity of the damage to the structure. A comparative study between a proper orthogonal decomposition (POD) based damage detection algorithm and proposed algorithm is presented. The results show that the proposed algorithm is efficient to identify the damage location and assess the severity of damage, called as the Damage Index (DI), under varying environmental and moving load conditions.

scholarly journals Mechanical Behavior and Failure Mode of Steel–Concrete Connection Joints in a Hybrid Truss Bridge: Experimental Investigation

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2549
Author(s):  
Yingliang Tan ◽  
Bing Zhu ◽  
Le Qi ◽  
Tingyi Yan ◽  
Tong Wan ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Failure Mode ◽  
Failure Modes ◽  
Local Buckling ◽  
High Strength ◽  
Testing Procedure ◽  
Gusset Plates ◽  
Truss Bridges ◽  
Study Results ◽  
Truss Bridge

The core part of a hybrid truss bridge is the connection joint which combines the concrete chord and steel truss-web members. To study the mechanical behavior and failure mode of steel–concrete connection joints in a hybrid truss bridge, static model tests were carried out on two connection joints with the scale of 1:3 under the horizontal load which was provided by a loading jack mounted on the vertical reaction wall. The specimen design, experimental setup and testing procedure were introduced. In the experiment, the displacement, strain level, concrete crack and experimental phenomena were factually recorded. Compared with the previous study results, the experimental results in this study demonstrated that the connection joints had the excellent bearing capacity and deformability. The minimum ultimate load and displacement of the two connection joints were 5200 kN and 59.01 mm, respectively. Moreover, the connection joints exhibited multiple failure modes, including the fracture of gusset plates, the slippage of high-strength bolts, the local buckling of compressive splice plates, the fracture of tensile splice plates and concrete cracking. Additionally, the strain distribution of the steel–concrete connection joints followed certain rules. It is expected that the findings from this paper may provide a reference for the design and construction of steel–concrete connection joints in hybrid truss bridges.

Modeling and Dynamic Characteristics Analysis of the Qiantangjiang Rail-Cum-Road Bridge

2014 ◽  
Vol 501-504 ◽  
pp. 1187-1193 ◽  
Author(s):  
Hui Wang ◽  
He Xia ◽  
Jia Wang Zhan
Keyword(s):  
Dynamic Characteristics ◽  
Mode Shapes ◽  
Plate Element ◽  
Truss Bridges ◽  
Beam Elements ◽  
Steel Truss Bridge ◽  
Steel Truss ◽  
Characteristics Analysis ◽  
Truss Bridge ◽  
Steel Truss Bridges

The dynamic characteristics of the Qiantangjiang rail-cum-road steel truss bridge is to analyzed by the Beam elements Midas model, beam-Plate element Midas model and plate element Ansys model, and the calculated results are compared with the field experiment data. The natural frequencies and mode shapes simulated with the plate element Ansys model are much closer to the experimental ones, indicating it can more accurately simulate the dynamic characteristics of steel truss structure. The results can provide a reference for modeling the steel truss bridges, and as the foundation of further static and dynamic analyses.

High Resolution Modeling and Modeling of Connections in Pony-Truss Bridges

2018 ◽  
Vol 2672 (41) ◽  
pp. 186-195
Author(s):  
Martin A. Butler ◽  
James A. Swanson ◽  
Gian A. Rassati ◽  
Eric F. Dues
Keyword(s):  
Finite Element ◽  
High Resolution ◽  
Primary Objective ◽  
Load Path ◽  
Element Analysis ◽  
Gusset Plates ◽  
Truss Bridges ◽  
Load Paths ◽  
Pinned Connections ◽  
Truss Bridge

Pony-truss bridges are usually modeled using simplifying assumptions, such as pinned connections and analyzing the trusses separately from the rest of the structure. Pony-truss bridges are also generally designated as possessing many Fracture Critical Members (FCM), a characteristic that requires more rigorous inspections. Eliminating or reducing the number of FCM is desirable as it reduces inspection costs. A high-resolution model of a pony-truss bridge was assembled in ABAQUS CAE that explicitly models the behavior of the gusset plates in the connections and the angles in the framed stringer connections. This model indicated alternative load paths that are potential sources of redundancy useful for retrofit or reclassification of bridges with FCM designation. Higher-resolution models of framed stringer connections were also made in ABAQUS CAE using solid elements explicitly modeling the bolted connections. The connections were loaded in tension; what the stringers must hold if they supply an alternative load path for the truss in the event of fracture in the bottom chord. The primary objective of the work described is to provide high-resolution finite element analysis results that can be used to create general behavior for lower-resolution finite element models used in fracture critical analyses to reclassify FCM as non-fracture critical. The results of high-resolution modeling reveal the behavior that is necessary to include in these lower-resolution models, as well as potential alternative load paths. Lower-resolution models are assembled in SAP2000 and matched to the higher-resolution models.

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