C.Y. Loh, Architectural Engineer

Interview by Bruce Haden

Assiduous readers of CA will have noted that while published work coming out of Vancouver over the last two decades has represented several design-oriented practices in the city–among them Patkau Architects, Peter Cardew, Henriquez Partners, Acton Johnson Ostry, Hotson Bakker, and Roger Hughes and Partners–the same structural engineer has often been listed in the project credits: C.Y. Loh and Associates. The firm’s work is characterized by painstaking attention to detail, and, more importantly, a conviction that structural engineering can participate in the design conversation as a full player. As a result, the firm has been an essential collaborator on some of the best architecture coming out of the West Coast.

The significance of this contribution has been acknowledged recently in an exhibition, Issues of Gravity: A Study in Collaboration presented by the University of British Columbia School of Architecture. The show was exhibited in the UBC SOA downtown gallery last fall and at the University of Washington School of Architecture in Seattle this spring.

CA’s Vancouver correspondent Bruce Haden interviewed C.Y. Loh about his career and design approach. The firm has four partners: C.Y., Lisa Sorensen, Kosta Marcakis and Paul Henry. Lisa Sorensen joined them for part of the conversation.

A recent exhibition of your work, Issues of Gravity, was subtitled A Study in Collaboration and emphasized your firm’s contribution to award-winning and published architecture. Is the creative collaboration with architects the critical component that distinguishes your practice?

We try our best to do good structural engineering, and to do this, we need to learn about architecture. We spend a lot of time keeping ourselves up to date by reading architecture magazines. We not only subscribe, but we read them! We try to interpret the work… and whether it succeeded or failed, in our opinion.

It seems as though you and your colleagues want to be part of architectural culture more than engineering culture.

(CYL) We are architectural engineers.

(Lisa Sorensen) The architectural part is the fun part, the engineering is just filling in the blanks. The engineering calculations are just tools, like typing is a tool. The interesting part of our job–and the frustrating part–is the architectural part.

(CYL) What I want to do for every project is to communicate through the work that I do. If I design a building structure or structural element, I want to show enough of the structure so that I can communicate to whoever comes to the building what kind of process I went through, and how I came up with the final design.

I try to convince my clients to give me the opportunity to communicate. If the architect covers up my work, there is no way that I can communicate with the public, my engineering colleagues and my client, who is usually the architect and sometimes the owner of the building. But, more importantly, I’m interested in communicating with the generation who is not here yet. I want them to look at the building sometime in the future and see what I have designed, and see that it was the right thing to do.

So, part of the success of the solution is that the visual expression is a direct manifestation of the rationality of the design process. It isn’t just the structural solutions that are important to display, but the way in which they respond to all the considerations of the project.


Can you give me an example with a specific building?

The Renfrew Library, by Roger Hughes and Partners Architects. It’s a new library, but it’s attached to a community centre. What was important to the owner, the architect and the community was that the library be designed to be as comfortable as a living room. The budget was tight, but the space had to be visually warm and structurally efficient. We decided that in order to satisfy these requirements, we would use a wood joist structure with plywood sheathing. We didn’t like the look of the exposed plywood; economically it was a good solution, but aesthetically… So when we chose the system I advised the project architect that I was proposing wood structural elements, but we should do something to improve the appearance of the plywood. Instead of using 2 x 10 wood joists at 16 inches on centre to span between the steel trusses, we went to 3 x 8s, and put them at 12 inches on centre. You see less of the plywood deck but you see the 3 x 8s and because they are closely spaced you read the wood joists, not the plywood. The result is very dramatic. The plywood sheathing is left exposed, but it becomes less significant visually.

And the roof trusses?

We specified a glulam beam for the top chord of the roof truss. And then in order to make the contrast with the bottom chord sharp and noticeable, we went to steel. We achieved what we originally wanted to, by having the warm feeling of wood but getting the long span capability out of the major structure. So where you want to see large-scale exposed structure we have a wood member, and you never confuse the structural role of the wood with the tensile role of the steel bottom chord. We also came up with very good connections between wood and steel so that the construction doesn’t read as heavy. All the elements were designed to be part of the architecture and part of the engineering. They come together through the effort of the architects and consultants so that not only the architecture and structure work hand in hand, but also the services–mechanical, sprinkler system, electrical; they are all in the right place.

Also, one way to produce a good design for a building project and stay within the budget is to integrate architecture and structure so that the structural components can be left exposed and be part of the overall architectural scheme.

Do you favour structural economy over structural expression, or does that vary?

For all the buildings we work on, we have to conform to the budget. The trick is to do that and also address the aesthetic aspect of the design. In structures, the costly items are the details. So when you don’t have a lot of money to spend on the structure, you have to come up with more reasonable details. Still, every time I try to come up with a certain detail to indicate our expressed concern about construction and detailing.

Can you give me an example of a connection where you considered the solution to be particularly successful?

At the moment we are designing a project for the YMCA in Surrey with Hotson Bakker Architects. In this project we have structural steel columns and concrete topping on a steel deck. There was discussion over how we were going to do the column base in terms of construction and in terms of aesthetics. We don’t want the column to simply emerge from a sea of carpet, in the same way that we don’t want to have a beam frame into a wall and have the joint covered in drywall. We think that it is a failure on the designers’ part if we end up with that kind of expression. And so in the example of a beam framed into a drywall panel with a column inside, what we do is we cut out the drywall, expose part of the column, and put in a steel plate so we acknowledge both the drywall finish and the structure behind.

In terms of the column base, we are going to put in a steel base plate which is larger than the size of the round column. The plate will be left exposed, and then the carpet finish will be brought up against the plate. That will both solve the aesthetics and help out with the construction process.

Have you always worked with design-oriented architects?

When I started my practice I was leaving the architectural office of Rhone and Iredale. If I wanted to work with other architects, I had to leave the company and set up my own. I pulled out the Yellow Pages, looked for Structural Engineers in British Columbia, and looked for what they did best, and in what style, in order to have a better understanding of the marketplace. I realized that there was a slot in the profession
that my previous experience at Rhone and Iredale and, before that, Ove Arup, would allow me to fill. I found that not only could I survive, but also have some success by working with design-oriented architects.

Could you give me another example of a project of yours where you thought the structural solution was particularly good?

I’d have to say the Skytrain stations that we are doing. We had the opportunity to design six of them.

Which architects are you working with?

We are working with Hotson Bakker on three of them, and with Architectura in joint venture with Walter Francl on the other three. Transit stations are more of a structural engineering problem than most buildings, although each station is designed by architects. The forms are very simple and functional, and this is the type of building where a structural engineer can contribute the most. Structural solutions for all these stations are very pure and very elegant because of the nature of the projects.

I would guess that these projects are particularly interesting because the design agenda of this Skytrain phase is that all the stations be distinct, as opposed to the first branch, where the stations shared a common kit of parts.

Each station has a different structural system and we tried to come up with different solutions for different requirements; we are using concrete, steel, masonry, and timber. We are very happy because the structural component of the construction cost is larger–we got a bigger proportion so we are doing more and we are happy because we can see more of our work at each station than we do with a typical building.

So there aren’t particular materials with which you prefer to work?

No, but there’s a reason for this. When I first set up my practice, I asked myself, can I survive? And one day I said yes, I will survive, if I know how to handle the business, and how to be flexible with structure and introduce different materials. So from that moment on, we used steel, concrete, masonry, whatever we think can provide the right combination for a particular project in order to lend aesthetic value and satisfy structural requirements.

Are there any other engineers, either historic or present day, who have influenced your thinking?

I think the engineers who associated with Frank Lloyd Wright and Louis Kahn.

It’s interesting that you would name the architects rather than the engineers.

Both are architects who would not compromise in terms of structural design. You were asked to start over again if they were not happy, particularly Frank Lloyd Wright. He designed most of the structures himself and used his engineers to confirm that whatever he had done was right.

What influence has computer technology had on your practice and how do you expect that to change in the future?

The computer is a tool that helps us to perform analysis only. The design idea is generated by the engineer behind the project.

So you don’t use the computer as a design tool?

No, we don’t use design programs to help us generate the design. We use a calculation program to help us to do the hard engineering work. This is because we don’t specialize in any one type of structure, like for example larger companies that specialize in concrete structures. We have a philosophy of looking at individual projects and then deciding which material we are going to use.

Wouldn’t the computer enable you to enhance your creativity in some circumstances?

What the computer helps us to do, apart from draw, is to look at many options in a short period of time. It also helps with the structural computations, but the design is generated by making reference to the architectural design and building code requirements. The computer doesn’t play a major part in our decision making. We design the structure, and we use the computer to confirm our assumptions.

In what ways has the practice of structural engineering changed during your career?

I think that the change that really affected our profession and our practices is a problem that was created by the profession, in large part by the architects in the early 1980s, when they made the mistake of giving up a big portion of their responsibilities by bending to pressure from developers and from the new profession of so-called project management.

Until the end of the 1970s the architectural and engineering professions were doing very well, but once we got in to the ’80s, architects were threatened by a number of lawsuits and wanted to control the damages. So they wanted the owner to hire additional consultants, and they limited their activities to architectural design and backed away from co-ordinating construction. From that moment on, I started to see the deterioration of our professions. Very often, the design is less than complete because the project management team does not allow sufficient time for co-ordination; often they are not design professionals. Some of these people, even when they have engineering or architectural backgrounds, fail to understand the issues. They try to remain in the design field, and to support themselves they created this profession. A significant number of them are not very good at it. I think that until we turn this situation around, we will continue to have problems.

Bruce Haden is principal of Haden Architect and a sessional lecturer in design at the UBC School of Architecture.