slightly wedge shaped bricks/stones used to build an arch

the basic condition for the safety of masonry is that the thrust line is kept within the middle third of a wall or column

building out masonry step-wise from each side until the stones meet in the middle (precursor to an arch)

a line passing down the wall of a building from the top to bottom which defines the position at which vertical thrust can be thought to act on each joint

the horizontal tension member or tie-bar across the bottom of a truss

french for “built-in”

beam one end of which is ‘built in’ to some rigid support

shearing load / area

a measure of the tendency for one part of a solid to slide past the neighboring part

stiffness of a material in shear (shear stress / shear strain). equivalent of Young’s modulus.

the amount of strain energy that may be stored in a structure without causing permanent damage.

any triangulated lattice girder

at 45 degrees to the warp/weft of a fabric

the yacht America won the race (which was then named for it) largely because American sail makers used tighter woven fabrics with the weave arranged to align tensions with the fibres while the brits used loose woven flax sails arranged haphazardly. The American sails allowed the yacht to sail in higher winds and turn in a tighter radius. When the Queen was told that America had come in first, she asked who came in second and was informed that no other ships were yet in sight.

the point at which a load must be applied so as to cause no twisting

if a wing isn’t rigid enough, an aileron can cause the wing to twist to such an extent that the opposite effect is achieved

the outside wood is tensioned to 4,000 psi while the inner wood is compressed

shell structure in which the load is carried in more or less continuous panels (think exoskeleton)

4’ 8.5” standard railway gauge derived from roman chariots. proved to be a major handicap (trains would be more stable and better able to go fast with a wider base)