Here you'll find a variety of crocodilian publications for sale, ranging from current books to fairly old publications and reprints. Other herpetological titles are also available. Zoo Book Sales. A highly recommended site for finding both new and used books on crocodiles, alligators and caimans. Books on other species are also available. articles & features:
Laying the First Course. 1  Start at the edge of the wall thatâs most visible, or the edge that butts up against another structure. If your wall goes across a slope, start at the lowest end. 2  Position the first stone in your trench. Make sure the stone is level from front to back and side to side.
Counterfort retaining walls are similar to cantilever walls except they have thin vertical concrete webs at regular intervals along the backside of the wall. These webs are known as counterforts. Counterfort retaining walls: 1  The counterforts tie the slab and base together, and the purpose of them is to reduce the shear forces and bending moments imposed on the wall by the soil. A secondary effect is to increase the weight of the wall from the added concrete. 2  Can be precast or formed on site.