Bridge Deck Slab Production with Conveyor Transport
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Solution Overview
Problem
Existing methods for producing bridge deck slabs are slow due to on-site formwork and reinforcement assembly, and anchoring techniques face challenges with low load capacity and bending stress issues.
Innovation Solution
A method involving the production of a bottom layer with cross beams at an angle of 70° to 90° from reinforced concrete, transported to the installation site using a conveyor device, where a top concrete layer is applied with optional reinforcement, and the bottom layer is removed before or after the top layer hardens, allowing for faster construction and improved anchoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If formwork and reinforcement are assembled on-site for each construction section, then the deck slab can be produced with proper structural integrity, but the construction progress becomes slow due to the time required for assembly and concrete hardening
Solution Approach 1:
The bottom layer with cross beams is pre-assembled at an assembly site before being transported to the installation site. This preliminary assembly includes installing formwork, reinforcement, and cross beams in advance, so that when the bottom layer reaches the installation site, these components are already in place and do not require time-consuming on-site assembly operations.
Solution Approach 2:
The deck slab production process is divided into separate stages: bottom layer assembly at an assembly site, transportation to installation site, and top layer application. This segmentation allows parallel operations where the conveyor device can transport bottom layers continuously while top layers are being applied at the installation site, eliminating the need to wait for concrete hardening before moving to the next section.
2Ease of manufacture
If tendons are anchored within the prefabricated slabs, then the anchoring can be simplified, but the load capacity of the anchors becomes insufficient
Solution Approach 1:
The anchoring system is changed from traditional anchors within prefabricated slabs to tendons that extend through the bottom layer and are anchored to the conveyor device. This parameter change in the anchoring mechanism allows for much higher load capacities while maintaining ease of implementation, as the tendon anchors can be directly connected to the conveyor structure.
3Productivity
If tendons are used to attach the bottom layer to the conveyor device, then the bottom layer can be transported efficiently, but the forces in the tendons cause bending moments that lead to high bending stress in the thin bottom layer
Solution Approach 1:
Cross beams are added at specific locations within the bottom layer to locally reinforce areas subjected to bending moments from tendon forces. These cross beams are strategically positioned to provide structural support where the bending stress is highest, allowing the thin bottom layer to withstand the tendon forces without excessive stress while maintaining transport efficiency.
Data Source
AI summary
“A method for producing a construction section of a deck slab for a bridge includes the following operations: producing a bottom layer composed of a segment and having cross beams, which are arranged in the transverse direction in regard to the longitudinal axis of the longitudinal bridge girder, from reinforced concrete; transporting the bottom layer having the cross beams for a construction section of the deck slab using a conveyor device from an assembly site to an installation site and lowering it into the installation position; producing a top concrete layer for a construction section of the deck slab on the bottom layer; removing the bottom layer having the cross beams for a construction section of the deck slab from the conveyor device and moving the conveyor device away from the installation site.”