# Study on Bending Performance of Tightly Spliced Truss-Reinforced Plate-Honeycomb Flat Beam
## 2 Experimental Programs
### Test Set-Up  
In this paper, the four-point bending loading was adopted for the specimens of densely spaced truss steel composited plate-combined honeycomb flat beams. A 500 kN jack is used for the test, and the reaction force is measured by setting the load sensor under the jack. The total length of the simply supported beam is 3000 mm, and the distance between the supports is 2800 mm. At 1000 mm from the supports at both ends, the load applied by the jack is applied to the two concentrated loading points through the distribution beam; the supports of the honeycomb flat beam specimen are fixed hinged supports at one end and movable hinged supports at the other end. The equipment used in the test cloth and its layout is shown in Figure 5.  
The test loading system adopts the form of force-controlled graded loading, and the load applied to the specimen of dense truss steel laminated plate-honeycomb composite flat beam is 10 kN at each level. To ensure that the applied load is fully transferred to the specimen, the load is loaded for 5 min at each level, the load is held for 3 min, and the deformation and damage of the specimen are read and observed at the end of the load holding. When the specimen is close to the yield load or the first crack starts to appear at the bottom of the concrete flange plate, the loading rate is reduced, and the load is taken at half level until the specimen is damaged. The loading rate is reduced when the first crack begins to appear at the bottom of the concrete flange plate, and the loading is taken at half level until the specimen is damaged. The measurement items of the test include the test load, the displacements at the support and loading points of the honeycomb composite flat beam and the medium \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Component** & **Materials** & **Yield Strength** & \
\begin{tabular}{c} **Ultimate** \\ **Tensile Strength** \\ \end{tabular} &
\begin{tabular}{c} **Compressive** \\ **Strength** \\ \end{tabular} \\ \hline Steel for beam 6 mm & Q355 & 351.0 MPa & 507.3 MPa & / \\ Steel for beam 8 mm & Q355 & 367.6 MPa & 524.4 MPa & / \\ Steel bar 6 mm & HRB400 & 415 MPa & 596.6 MPa & / \\ Concrete for slab & C30 & / & / & 39.9 MPa \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Material properties of composite beams. Figure 5: Experimental study on the bending performance of combined flat beams. part of the span, the vertical stress-strain distribution along the section of the purely bending section of the steel beam, the equivalent force distribution around the first hole of the bending and shearing section, the strain distribution in the compression zone of the concrete flange slab, the tensile strain distribution of the reinforcement in the splice of the composited plate, and the crack development during the stressing process of the concrete slab. The arrangement of displacement gauges and strain gauges is shown in Figure 6.  
Among them, the specific arrangement of strain gauges is as follows:  
1. One strain gauge is arranged on the upper flange and lower flange of the purely bending section of the specimen to detect the stress-strain of the upper and lower flange of the steel beam;
2. Three resistance strain gauges were arranged at the pier of the purely curved section of the honeycomb beam at a height spacing of 80 mm along the beam cross-section to check the development of vertical strain along the beam cross-section in the purely curved section;
3. Four resistance strain flowers were arranged around the first honeycomb hole in the bending and shearing section, i.e., 45\({}^{\circ}\) and 135\({}^{\circ}\) directions, to observe the change in equivalent force in the hole during the loading process;
4. Three strain gauges are set at 180 mm spacing transversely on the upper surface of the concrete slab to detect the compressive strain distribution on the upper surface of the concrete slab;
5.