Questions

Note, the project structural engineer Paul Pensy is quoted extensively throughout this section since he was kind enough to email clear and concise answers to our questions; his words are indicated in italics and attributed appropriately. We have also added our own comments to show we understand his answers.

1. What is the strength of the timber and or masonry used in the field?

Although there was evidence timber or lumber would be used in this project, the engineer was kind enough to describe timber they often use.

“The values of the timber vary between the species that we specify; Southern Pine No.2, Douglas Fir Larch No.2 and Hem Fir No.2. These values can be found in the NDS specifications, [dependent] upon the type of application (tension, compression, flexure, etc.). We specify hollow load bearing block as required in ASTM-C90, grade N1. The mortar strength is a minimum of 2500 psi (type M) for below grade work, minimum of 1800 psi (type S) for above grade and the prism strength is 1500 psi.” –Paul Pensy, Project Structural Engineer

2. How are connections made in the field?

“In reference to the bolted connections, they are typically snug tightened because of their use in our design.” –Paul Pensy

The site supervisor, Doug Marbach, also described this to us.

3. How is the [masonry] structure tied down to the floor?

“The masonry is actually tied to the foundation grade beams and not to the floor. This is achieved by the embedment of the rebar into the foundation and extends up into the masonry wall. The grout then bonds the rebar to the masonry walls, giving them their strength and stability.” –Paul Pensy

We saw evidence of this in photographs, provided by Sergio Aranda, of the site before we visited .

4. How systems were used to transfer lateral loads?

“The lateral loads were transferred by shear walls on three sides and the 'K' brace (braced frame), near the front of the building. The transfer is made by the connections of the roof decking to the shear walls and then the roof joist, which gets forces transferred from the roof decking, to the braced frame.” –Paul Pensy

In other words, lateral loads in the rear of the building are transferred from the roof decking to the roof joist, and then to the shear walls. In the front of the building, lateral loads are transferred through the braced frame to the shear walls.

5. How do you specify the lumber?

There was no lumber used in this project.

6. What is the cost lumber?

There was no lumber used in this project.

7. How is lumber supplied to the construction site? Name of supplier or fabricator?

There was no lumber used in this project.

8. How do you specify the masonry?

“The specifications for masonry, like most structural items we specify, is the industry standard. This helps to control costs, ease of installation and also lets us use a constant design.” –Paul Pensy

Photographs of the masonry units delivered confirm they are standard units.

9. What is the cost of masonry?

We were unable to obtain cost data.

10. How is masonry supplied to the construction site? Name of supplier?

“The masonry is typically supplied by a local supplier and delivered by truck.” –Paul Pensy

From the packing label on each pallet, it looked like the masonry units were delivered in care of the masonry contractor.

11. How are dimensions controlled in the field? Are there any tolerances?

“The specific tolerance's are all code driven and there is minimum, maximum, vertical and horizontal dimensions that need to be met. Various methods can accomplish this, two examples are strings set up by a surveyor and a laser, also set up by a surveyor.” –Paul Pensy

The site supervisor and master mason we interviewed suggested they generally use the least technologically advanced options when building, usually just eyeballing the work.

12. In what lengths is lumber delivered to construction sites? What is the maximum delivery length for lumber?

There was no lumber used in this project.

13. What is a diaphragm?

A diaphragm transfers lateral loads such as wind and earthquake loads to shear walls or to frames primarily through in-plane shear stress.

14. What is a shear wall?

A shear wall resists, primarily by in-plane shear strength, the lateral loads applied to a structure.