The web splice of a plate girder is an important structural component that connects two web plates together to form a longer girder. The forces acting on the web splice are crucial in determining its strength and stability. The correct answer to this question is option 'C', which states that the forces acting on the web splice are shear and bending forces.

Shear Forces:
Shear forces are created when two or more forces act parallel to each other and in opposing directions. In a plate girder, shear forces are created when loads are applied to the top and bottom flanges, causing the web to experience shear stress. The web splice must be designed to resist these shear forces to prevent the girder from failing.

Bending Forces:
Bending forces are created when a load is applied perpendicular to the length of the beam. In a plate girder, bending forces are created when loads are applied to the top and bottom flanges, causing the web to bend. The web splice must be designed to resist these bending forces to prevent the girder from sagging or breaking.

Shear and Bending Forces:
The web splice of a plate girder experiences both shear and bending forces simultaneously. The shear forces cause the web to experience shear stress, while the bending forces cause the web to bend. The combination of these forces puts a lot of stress on the web splice, and it must be designed to resist both types of forces to ensure the girder's stability and longevity.

Conclusion:
In conclusion, the web splice of a plate girder experiences shear and bending forces simultaneously. Both types of forces must be considered when designing the web splice to ensure its strength and stability. By taking these forces into account and designing the web splice accordingly, engineers can create strong and durable plate girders that can support heavy loads and withstand the test of time.