Master Ketnar continued. “Rudi is second to none of my students in working with wood as a building material, and we believe you will need his expertise and mine in constructing your scaffolding and your full-scale pattern. Master Edders has taught everything he knows about stone, the carving of stone, and the selection of stone to Brice; they will alternate at the quarry and at the building site. And Master Renold specializes in reinforcement, as does Emmit. Master Renold foresees a possible problem in scaling up, and he already has a solution should the full-scale model reveal he is correct.” He rubbed his hands together in anticipation. “So, Trainee Abidela, are you ready to go to work?”

•   •   •

Building the full-scale model out of wood took all fall and winter. It wouldn’t have been possible for the work to have continued through the winter at all except that the Sisters of Betane of the Ax cleared their sanctuary as a place to do the construction. “We owe Herald Mags and the Crown itself for uncovering the fiend who was persecuting women two decades ago,” the Prioress said. “And the project will be of immense value to the City in which we live.” Then she smiled. “Besides, this pattern-model will be of wood, yes? An ax hews more than men. Betane will approve.”

As expected, problems did arise in the building of the full-scale model. The first problem was with the spandrels, the supports on either end of the bridge. According to the math and Abi’s design, the bridge had to be thin at the middle but broaden downward at each end in order to distribute the weight properly against the bank. The load-bearing arch would actually form the bottom of the span; the spandrels and roadbed would be built atop that. But careful measuring showed that the spandrels would be under water during the worst flooding, according to all of the records they consulted.

That would put potentially intolerable force against the spandrels and create a problem similar to the one that brought down the last bridge.

At this point the model was mostly on paper and a set of huge plans drawn on linen fabric for durability. Abi’s Gift was not going to help her here.

She stared at the plans showing one of the spandrels, frowning, and thought, noting how the roadbed lay above the arch. I don’t want pillars between the roadbed and the arch because that would just replicate the problem the first bridge had. We need holes of some kind in the spandrels, but what will distribute the forces evenly and put them right back where I want them, into the riverbank?

Then, after two days of staring at the plans, it occurred to her. Curves had distributed the forces evenly in the initial design. Why not go back and use arches again? Would arches within arches work?