Load demands on the MAST crosshead due to specimen attachments are determined for each experiment. In general, the following guidelines will reduce potential problems with crosshead connections.
- When possible, specimens attached to the underside of the crosshead should span the 4.5 ft by 4.5 ft central box of the crosshead. For specimens that cannot span this distance, MAST provides a stiffening plate to reduce the localized effects of the point load on the crosshead.
- Specimens put into compression will have fewer crosshead attachment issues than those put into pure shear or shear/tension forces.
- Specimens that are placed diagonally to the crosshead may require large spreader systems (provided by the user) to be attached between the crosshead arms. The specimen then attaches to these diagonal spreader frames.
- Masonry and concrete specimens generally require concrete footers and headers with reinforcing to provide shear capacity at the crosshead interface.
- Box section 4'-8" wide by 5'-5" deep
- Tip-to-tip 29'-3"
- Weight 94 kips
- Standard vertical neutral axis positions 18'-3", 19'-9", 21'-3", 22'-9", 24'-3", 25'-9", 27'-3", 28'-9"
Non-threaded, 1 5/8” holes are drilled into the bottom plate of the crosshead. Access is provided to the inside of the crosshead for tightening bolts. The nominal hole pattern on the underside of the crosshead is shown in the figure below.
The four-hole tabs at the side of the vertical actuator attachment sites are not intended for specimen use.