Mcheza hawi kiwete, ngoma yataka matao

 

Methali (proverb)

Mcheza hawi kiwete, ngoma yataka matao.

Meaning: A dancer will not be crippled by dance-moves, one should move as much as possible since dancing calls for grace.

Tao - arch, curve, especially arches on building’s doors or windows. Matao is plural – arches, curves.

Despite being primarily for structural support, arches are taken as symbols of gracefulness on architectural designs.

An arch is a structure of bricks held together by a keystone at the top. A keystone (or capstone) is the wedge-shaped stone at the apex of a masonry arch or typically round-shaped one at the apex of a vault. In both cases it is the final piece placed during construction and locks all the stones into position, allowing the arch or vault to bear weight. Keystone is often used metaphorically for an essential part on which the whole depends.

Although a masonry arch or vault cannot be self-supporting until the keystone is placed, the keystone experiences the least stress of any of the wedged bricks, due to its position at the apex. Old keystones can decay due to vibration, a condition known as bald arch.

Deterioration of the mortar within masonry arches can cause the masonry units within the arches to shift, or even fall out of the arch. Loss of masonry and mortar can alter the load path within the arch system, cause the arch to sag and spread. This can result in transfer of the building loads into the window or door frames. Since routine repair and renovation works are usually done on non-structural components of buildings like window or door frames, care must be taken when replacing existing frames of an unreinforced brick building to make sure that no masonry loads are being carried by the frame prior to removal. If the arch is beyond repair with mortar/epoxy filling, and therefore needs to be rebuilt, it requires a carefully planned and implemented phasing of shoring, rebuilding, and load transfer (e.g. needle beams to temporarily support the masonry above the arch to allow for rebuilding and load transfer back to the arch).

To avoid having to rebuild, the arch is constantly monitored for repairs. Many arches’ keystones are usually adorned with cladding and figurines to make any effects of vibrations less obvious to lay onlookers. But masons monitoring the keystone can investigate signs of vibration and commission repairs. The building still remains as it looked before repair.

The fear of vibration on matao (arches) does not stop the utilization of the building to engage groups of people in and on the building in varied activities. Committed monitoring of the arch ensures that it is maintained to avoid load transfer that necessitates rebuilding.

 

References

Ching, Francis D.K. (1995). A Visual Dictionary of Architecture. New York: John Wiley & Sons, Inc. p. 12.

Smith, Nathaniel B.; Milan Vatovec (2015). Divine Design: Renovating and Preserving Historic Houses of Worship. In Articles, “Structural Rehabilitation”. Structure Magazine.

TUKI (2001), Kamusi Ya Kiswahili-Kiingereza; Swahili-English Dictionary. Published by Taasisi ya Uchunguzi wa Kiswahili (TUKI), Chuo Kikuu cha Dar es Salaam, Tanzania.