For my structures class at Ohio State, we had to investigate a crack in a structure. For the report we had to include a description of the crack, the reason for the crack,and our solution.

1. To: Bill Shepard
From: Ryan D. Blessing
Subject: Structural Crack Report
Date: 26 November 2012
As requested I have found a structural crack and done the research that entails its description, the
reason for its occurrence, and solutions to the crack. The details are explained as follows:
Description of Crack
The crack is found on the West side of Hitchcock Hall at Ohio State University, 2070 Neil Ave Columbus,
OH 43210, on a retaining wall that faces the East side of the Knowlton School of Architecture. The wall
is approximately 18’-0” to 20’-0” long and 10’-0” high, and acts as a retaining wall to the soil that lies
beneath the walkway leading to Hitchcock Hall. The height of the soil that the wall is retaining is
estimated to be 6’-0.” The retaining wall has multiple cracks that include inside the mortar joint as well
as the faces of the brick. The crack in the mortar joint runs parallel with the stairs that lead to the
entrance sidewalk of Hitchcock. The crack in the faces of the brick can be found in various locations on
the wall.
Reason for Cracks
The following are reasons that are associated with the cracks in the structure:
1. Moisture behind the wall
2. Earth pressure
The first reason for cracking is there is moisture behind the wall. The wall is assumed to be a CMU wall
with a concrete footing, and a brick veneer. The top of the retaining wall acts as a flower pot for the
majority length of the structure. Since the top portion of the wall is exposed to rain for the plants, it is
an accurate assumption to think there is not adequate waterproofing to sustain moist soil on a regular
basis. Therefore, moisture has been getting into the wall thus causing brick expansion, efflorescence,

2. and spalling of the brick face. Brick expansion occurs due to bricks never shrinking after being exposed
to moisture. They are on a constant swell cycle causing cracks to occur in the brick face. Most of the wall
has white streaks of efflorescence. This explains there is definitely moisture behind the wall, and is
pushing to the surface. The water coming to the surface stains the wall due to minerals from the brick.
The top portion of the wall, as seen in pictures, has terrible spalling where the brick face no longer has
any texture and has discoloration, also a consequence of moisture.
The second reason for cracking, especially in the mortar joint near the stairs, is due to earth pressure on
the wall. The reason this is a possibility for cracking is because of the observation found, the protrusion
of the brick face near the stairs. This is caused by the earth pressing against the wall, and over time if the
wall is not properly reinforced, it can cause cracking in the mortar joint, as well as brick face protrusion
from excessive pressure.
How to Repair
The first option on how to repair the wall is to not do anything. The wall is old and building a new one in
its place would be the most aesthetically pleasing option in repair.
The second option could be to strip the brick face and re-waterproof the CMU wall that is found behind
the brick face. This would eliminate efflorescence for the future, and a new brick face would be installed
that is not stained with efflorescence .
The third option is to use SikaPronto® 19 TF (Tack Free) page C110 in the Sika Product catalog. This
product can be used in cracks below or above grade on concrete or mortar. It can be applied by roller,
squeegee, or broom. The material is spread over the crack and then removed once the product as
penetrated into the cracks. This Sika product acts as a sealer and helps prevent chloride-ion’s from
penetrating the wall surface. This material would be used on only cracks in the mortar joints to hopefully
slow the advance of moisture and efflorescence on the rest of the wall, as well as reduce cracking due to
earth pressure.

3. References
Sika Corporation®, Construction Products Catalog.