Oregon Caves Historic Structures Report

PART V
Interior Assessment and Recommendations (continued)

Heavy Timber Frame

The Chateau's heavy timber interior structure allows for the vast open spaces in the lobby, dining room and lounge, and coffee shop. This portion of the structure rises from the floor of the second floor through the third and fourth floors, terminating at the floor joists of the fifth floor. The main columns, measuring approximately 30" in diameter, support the main cross members running east to west through the structure. Secondary cross members run north to south over these, providing support for the floor structures of the third, fourth, and fifth floors. The columns bear on the concrete walls of the first floor, the spacing narrowing as the walls and gorge taper towards the east. The subtle gray color of the columns is due to airborne particles of cement that settled on the wood when sacks were beaten against them during construction.

Simulated traditional joinery in the lobby.

The main cross members, bearing directly on the top of the columns, measure approximately 18" x 24". All joints in these members occur over columns, and are covered with applied wood decoration that simulates traditional joinery but serves no structural function. This decoration is mounted with metal spikes behind the phony wedges and loops. The secondary cross members are attached to the main members with mortise and tenon joints at each end. The tenon is almost the full dimension of the secondary cross member at these joints.

Typical heavy timber column.

The heavy timber frame has been altered in two locations. During the 1954 remodel of the coffee shop, the column in the center of the room was replaced with a smaller diameter steel post to facilitate patron circulation. A steel plate is welded to each end of this post to provide bearing. The 1964 flood caused the collapse of the dance floor, and the main cross member (running east-west) at the south side of the north wing was replaced at the east end by two laminated beams resting on the original column. The east end of this replacement beam bears on the original shelf in the concrete foundation. The foundation has engaged rectangular concrete columns at the second floor level on the east and west walls with a notch to fit the end of the beams.

Check in dining room column.

Taken as a whole, the heavy timber system is sound. There are only three areas of concern in the system, based on a visual inspection. In the dining room, the columns at the north end near the creek diversion are experiencing potentially serious checking. There is no lateral displacement of the overhead beams at this location, but the check runs almost all the way through the column and is approximately 3/4 of an inch wide at the outside edge. The beam above this column running to the east is also experiencing moderate checking.

Where the column was replaced in the coffee shop, there is lateral displacement of the main beams. These beams seem to be shifting on the steel plate, and not bearing evenly. The beam to the west of this column has been bolted together, as it was seriously checked. The third area of concern is in the lobby. At the north end of the reception desk, the beam to the east of the column at the corner of the desk is checking moderately.

A final note on the heavy timber in the lobby is that the columns are experiencing slight checking, but are suffering more from abrasion damage by chairs and objects carried through the space.

Recommendations for Treatment: Heavy Timber

While the heavy timber system appears to be performing well, there are a few areas of concern. The recommendations for the system are as follows:

• An engineer should be employed to inspect the three locations where moderate to serious checking is occurring. These are located in the dining room and lobby, as mentioned above. The members should be analyzed to determine if they are performing as they should, and are able to carry their load. The members may need to be repaired or reinforced as required, possibly by bolting. The bolts in the coffee shop beams are intrusive and non-historic, and should have been installed in a more sensitive fashion. Recessing the bolt heads and inserting wood plugs over the bolt heads would make them less intrusive.

• The columns in the lobby should be protected from abrasion, as it is destroying the historic finish on these members. Chairs should not be placed near the columns, and objects such as ladders and other maintenance equipment should not be leaned on the columns to rest.

orca/hsr/hsr5d.htm
Last Updated: 22-Sep-2001