Glass unit masonry panel
A non-loadbearing glass block panel in an exterior or interior wall, designed by the empirical rules of TMS 402-22 Chapter 14: the panel's area and dimensions for its units and wind pressure, its support, expansion joints, mortar and joint reinforcement, and the line load its head and jamb supports must carry. US and metric units.
Edition. TMS 402-22 is not on hand. The chapter was read in TMS 402-16, where it is Chapter 13 (pp. C-191 to C-195). TMS's overview of the 2022 changes says the chapter became 14 and its limits were put in tables, with no other change listed; references give the 2022 number with the 2016 one in brackets. Figure 14.2-1 (13.2-1) was read off the scanned page at its grid lines.
Inputs of the glass unit panel #
- Panel: exterior or interior; standard units (at least 3-7/8 in.) or thin units (3-1/8 in. hollow, 3 in. solid); the unit's face size (for panels one unit wide or high); width and height between structural supports; curved or not.
- Strength level wind pressure: the components and cladding pressure at strength level (ASCE 7-22). Interior panels above 16 psf follow the exterior rules.
- Support: panel anchors (spacing, embedment in the joint, fasteners per anchor) or channel-type restraints (the panel's recess in them); the deflection ratio of the supporting members; whether the panel stands on wood construction, and its installed weight.
- Joints and mortar: expansion joint thickness at the top and sides, mortar type, joint reinforcement spacing.
There is no auto-design: the panel's size is the architect's and the rules are limits.
Checks performed #
| Check | Basis |
|---|---|
| Area: exterior standard units by Figure 14.2-1; thin units 100 ft²; interior 250 / 150 ft² at 16 psf or less | 14.2.1 to 14.2.4 (402-16 13.2.1 to 13.2.4) |
| Width and height between supports: 25 by 20 ft, thin units 15 by 10 ft | same |
| Thin units outside: wind pressure at most 32 psf | 14.2.2 (13.2.2) |
| Unit thickness | 14.1.3 (13.1.3) |
| Supporting members deflect at most l/600 | 14.3.2.1 (13.3.2.1) |
| On wood: 40 psf and 12 ft at most, vertical expansion joint | 14.3.2.2, 14.3.2.3 (13.3.2.2, 13.3.2.3) |
| Panel anchors 16 in. apart at most, 12 in. into the joint, two fasteners; or 1 in. in channels; no anchors for a single unit | 14.3.3 (13.3.3.1 to 13.3.3.4) |
| Line load for the head and jamb supports: the greater of 0.6W and 200 lb/ft | 14.3.3 (13.3.3) |
| Expansion joints at least 3/8 in.; Type S mortar outside; joint reinforcement 16 in. apart at most | 14.4, 14.6, 14.7 (13.4, 13.6, 13.7) |
The support line load takes each support as carrying half of the panel spanning to it (the head with the panel spanning vertically, the jambs with it spanning horizontally): a conservative split of a two-way panel. The drawing is the panel elevation with its supports.
Limitations #
- The chapter is empirical: no stresses in the glass units are calculated.
- Figure 14.2-1 is digitized: areas are within about 2 percent of the printed curve. Pressures above the curve's start (about 102 psf) are not covered; below its end (about 15 psf) the area is held at the end of the curve, about 264 ft².
- The supporting frame, its members and anchorage, the base emulsion and fire ratings (listed assemblies) are not designed.
Verification examples #
Verification status: 15 values compared in 10 examples (8 published, 2 hand calculations from the cited equations): 15 within tolerance, 0 recorded deviations. Code basis: not yet recorded for this module.
Published: the area and dimension limits of TMS 402-16 13.2.2 to 13.2.4 and Figure 13.2-1 read at its 16, 32, 48, 64 and 80 psf grid lines (compared within 5 percent, the reading accuracy of a scanned chart). Hand calculations: the support line load. No worked example of a glass block panel is on hand.