Various stresses in jointed plain concrete pavement with slab size of $3.5 \mathrm{~m} \times 4.5 \mathrm{~m}$ are denoted as follows:
Wheel load stress at interior $=S_{w l}^{i}$
Wheel load stress at edge $=S_{w l}^{e}$
Wheel load stress at corner $=S_{w l}^{c}$
Warping stress at interior $=S_{t}^{i}$
Warping stress at edge $=S_{t}^{e}$
Warping stress at corner $=S_{t}^{c}$
Frictional stress between slab and supporting layer $=S_{f}$
The critical stress combination in the concrete slab during a summer midnight is
- $S_{w l}^{c}+S_{t}^{c}$
- $S_{w l}^{e}+S_{t}^{e}+S_{f}$
- $S_{w l}^{e}+S_{t}^{e}-S_{f}$
- $S_{w l}^{c}+S_{t}^{c}+S_{f}$