Structural Design for Architecture
Fig. 6.7 St Peter's Basilica,
Rome, 4th century CE. A fully
triangulated timber structure,
which exerts no lateral force on
the walls, spans the central part
of the building. The use of this
type of timber structure has
allowed the creation of a large
interior space without the need
for the elaborately buttressed
supporting walls which would
have been required had a
masonry vault been used (after
Mark).Fig. 6.8 Left. St Paul's Outside the Walls, Rome, 4th
century CE. This perspective drawing illustrates well the
advantage of using a triangulated timber roof structure
rather than a vault. The thinness of the walls is well shown
(after Piranesi).Fig. 6.9 Below. St Paul's Outside the Walls, Rome, 4th
century CE. Cross-section (after Rondelet).184