Leveraging Digital Tools for Holistic Design Collaboration

Transcription

1 ctbuh.org/papers Title: Author: Subject: Keywords: Leveraging Digital Tools for Holistic Design Collaboration Kermin Chok, Technical Director, Meinhardt IT/Computer Science/Software Optimization Structure Technology Publication Date: 2011 Original Publication: Paper Type: CTBUH 2011 Seoul Conference 1. Book chapter/part chapter 2. Journal paper 3. Conference proceeding 4. Unpublished conference paper 5. Magazine article 6. Unpublished Council on Tall Buildings and Urban Habitat / Kermin Chok

2 TS01-02 Leveraging Digital Tools for Holistic Design Collaboration Kermin Chok Meinhardt Group Design (Singapore, Kermin Chok Biography Kermin Chok is currently a Technical Director in the Civil and Structural division at Meinhardt. He is a member of the firm s Global Design Group, which is responsible for accelerated concept development, internal quality control and knowledge sharing. In his role, he helps advance the technological edge as it relates to engineering and design collaboration. He leads the development, deployment and integration of custom and off-the shelf workflow solutions tailored to the firm s needs. Kermin s research interests center on digital design as it relates to architectural-engineering collaboration, workflow compression and structural optimization. His work in these areas has been previously published in the journal of the Association for Computer Aided Design in Architecture (ACADIA) and the International Journal for Architectural Computing (IJAC). Previously, Kermin worked at Skidmore Owings and Merrill (Chicago) and Halvorson and Partners (Chicago). In his past roles, he has contributed to many large scale projects such as the Burj Dubai, Trump Tower (Chicago), Infinity Tower (Dubai) and Central Market Development (Abu Dhabi). Exposure to these large projects has shaped his thinking on the future of design collaboration and engineering. He holds a Bachelor of Science (Civil Engineering) with Honors from Northwestern University and a Master of Engineering (Civil Engineering) from MIT. He is currently based in Singapore. 50

3 Abstract Digital design tools have transformed the way architecture design is imagined and executed. 3D surface modeling and custom scripting are now standard among architectural designers in the field. Catering to this wave of change, software vendors routinely update their software with an ever growing list of features. These tools have the benefit of allowing more freedom in architectural expression while allowing the team to accelerate their internal processes. In this accelerating environment of design, this paper proposes a rethink of what design collaboration means between architect and engineer. The paper demonstrates how a smarter leverage of software and focused custom programming can lead to dramatically more efficient workflows. Custom linkages between architectural geometry and structural analysis are illustrated along with structural morphology and optimization. The paper proceeds to illustrate how these new workflows have the extended effect of enhanced communication both within a firm and externally. Finally, the paper concludes by illustrating how a broad base of custom tools allows the engineering team to collaborate with the architectural team in new and creative ways. This is illustrated through a schematic layout of columns in a floor slab and force trajectory visualization. Keywords: Structure, Optimization, Collaboration, Architecture, Rhino 51

4 Introduction The building industry is currently awash in a plethora of digital design tools. Each tool seeks to address a specific need in the design process starting from light conceptual modeling to detailed building information modeling (BIM). For example, in larger architectural projects, conceptual studies are often undertaken with a mix of physical models and rapidly evolving parametric models. This rapid adoption of digital tools have allowed for a new mode of architectural expression previously impossible where in architects can digitally mold their designs instantaneously. In the delivery phase, BIM is a key tool in order to effectively deliver these increasingly complex projects. In this evolving design environment, software vendors routinely update their products yearly with an ever growing list of features. While compatibility within their own design platforms has increased, the linkages between platforms utilized by industry specialist are often insufficient to keep pace with evolving design practices. Software innovation in the building industry has typically been targeted at the architectural and contracting industries due to their commanding size. The time required for architects to reshape a building for a client s input and approval has minimized. The structural engineering industry has typically lagged with software innovation and has not kept up with the current speed of architectural innovation. The problem is exacerbated by attempting to fit a traditional structural engineering approach, better suited to simple building geometry, to projects that involve geometric complexity. If the structural engineer does not keep up with the current innovations in the architectural digital domain, they risk becoming marginalized in the conceptual and schematic design processes. The conventional means of concept collaboration, wherein an engineer uses their judgment to converge on efficient architectural and structural solutions, followed by initial design checks to confirm the suitability of the proposed concepts, may become obsolete in the digital frontier. This paper explores how the structural engineering process might be re-thought to provide collaborative solutions that the traditional engineering process lacks. The paper explores challenges and solutions ranging from working with architectural geometry in the fluid conceptual phase, internal process efficiency to communication and collaboration with different members of the design team. Types of Collaboration In the building design process, project participants include, but are not limited to, the client/developer, project management team, architectural design team, engineering consultants and contractors. Every party has different, sometimes competing, priorities. In addition, different parties have different preferred mediums of communication and software platforms, which can complicate project execution. For example, the client may desire an iconic but cost effective design and their preferred medium of communication may be reports or s. Meanwhile, the architectural team may be seeking to deliver a 52

5 project that pushes the edge of design while adhering to the design brief. Their primary medium of communication is usually visual which may include sketches or detailed renderings. On the other end of the spectrum is the PM and contracting team who has safety, constructability and cost on the forefront of their mind. Their communication and project execution platform may be detailed BIM. In this fragmented communication environment, design intent and project requirements can be easily misinterpreted. This paper proposes that the smarter leveraging and linking of existing software platforms, rather than the use of more software platforms, as a solution to this challenging design environment. In order address such challenges, the paper frames proposed solutions in three radiating spheres of innovation: efficiency, communication and collaboration. This is illustrated conceptually in Figure 15. Figure 15: Spheres of Innovation Internal Efficiency Internal efficiency is the first step for any member of the design team to effectively contribute to the design process. Digital design tools, while allowing un-paralleled architectural freedom, has the additional characteristic of accelerating the design process. Architectural design iterations occur in ever compressing time scales, and engineering consultants must accelerate their internal process to provide timely feedback to the design team. If the design team continues with the conventional fragmented internal processes, the engineering studies can easily be two or three design iterations behind, subsequently resulting in forced solutions further along the design process. Leveraging architectural geometry A critical first step in closing the gap between architectural and structural design is being able to use the surface massing model that is generated at the early stages of the design process. In the initial stages of the design project, the design team is primarily concerned with overall geometry and massing and its relation to floor areas, rough environmental studies and feasibility of the structural system. Illustrated in Figure 1 is an example massing model that the structural team might receive from the 53

6 architectural team. These forms are usually generated parametrically using software such as Rhino- Grasshopper or Bentley Generative Components. Working with such surface geometry using traditional structural engineering drafting platforms such as AutoCAD can be very challenging, due to program limitations and incompatibilities. The loss of geometric information during import/export procedures between different software platforms only compounds the challenge. Figure 16: Example Architectural Tower Massing In order to address this challenge, custom digital design tools in Rhino-Grasshopper have been built which allow the quick and easy extraction of structurally relevant information. While the architectural design team might be primarily concerned with floor areas and the sensitivity of the proposed massing to the site, the structural team is looking for key information such as the total gravity load, base shears and overturning moments due to lateral loads. Illustrated in Figure 17 are two custom components that compute the relevant code specific wind pressure for the site and key structural information derived from the architectural surface geometry. Figure 17: Custom Rhino-Grasshopper Components 54

7 Figure 18: Typical Structural Information Layered on Tower Massing Illustrated in Figure 18 are key structural information such as wind pressure, story shears and overturning moments along the tower s height. In addition to computing structural information, other custom components that allow direct linkages to structural analysis have been implemented by the author. Working within a single geometry environment has the advantages of preserving data integrity and also accelerating the design and analysis process. An accelerated process allows for the structural implications of geometry modifications to be understood in almost real time. This allows the structural engineer to provide efficient structural solutions relevant to the current design iteration. Structural Morphology Figure 19: Direct Linkages to Structural Analysis During the design cycle of most projects, geometry is constantly adjusted due to changing design requirements or design exploration. This is especially true in the schematic design phase of projects, 55

8 where rapid evaluation of structural performance is necessary. The architectural team may be exploring parameters such as building height or subtle adjustments in tapers or other architectural expressions. In the structural realm, engineers seek to understand the influence of varying structural member properties such as wall thickness or beam sizes on critical structural performance such as total building drift or inter-story drift. These studies have traditionally been performed with manual point-and-click operations. While such manual manipulation of structural models is adequate for projects of moderate size, buildings of larger scale and increasing complexity can quickly render this process unworkable. Furthermore, more value is added to the design process by studying the geometry of the primary structural system rather than focusing on the member level performance contributions. Nonetheless, the affects to individual members can also be realized. In order to efficiently accomplish structural geometry studies, custom programs that automate this process have been developed by the author. The program morphs the structural analysis model according to parameters, runs selected analysis (e.g. Linear Static, Natural Frequency, Spectral Response) and generates a report that documents the sensitivity of the performance measure (e.g. drift, natural periods, base loads) to the geometry parameter. Illustrated in Figure 20 is a screenshot of the custom program. Figure 20: Custom Structural Morphology Program Illustrated in Figure 21 is an example parametric study of varying the core geometry of a tower. The core is morphed in 1m increments along the y-axis. Over the course of six runs, the core has a y-direction depth ranging from 7m to 13m. In this situation, the effect of the geometry modification on the building natural periods is documented. 56

9 Structural Optimization Figure 21: Parametric Core Study In tandem with the tools to explore a structure s geometry, optimization techniques are another critical tool that can accelerate structural analysis and design. Structural optimization is a mathematical approach to satisfy a set of deflection and strength constraints while minimizing the amount of material used. Another custom program developed by the author interacts with a finite element solver and determines the optimum distribution of structural material to walls and beams. See Figure 22 for a screen shot of this custom program. Figure 22: Custom Multi Constraint Optimization Solver Illustrated in Figure 23 is a simple three span truss with two cantilevers. In this example, control of 57

10 deflection at the mid span and two cantilever tips are sought while meeting imposed minimum and maximum size constraints on the structural members. Such custom optimization tools can greatly accelerate the structural exploration process and minimize the often tedious trial and error approach to structural sizing. Furthermore, member size constraints can be collaboratively established by soliciting architectural and constructability concerns. Figure 23: Example Optimization Model 58

11 Communication In all firms, communication occurs both internally and externally. In most structural design groups, junior level engineers are tasked with analysis and design while more senior engineers are responsible for client contact and management of numerous projects. Due to the differing responsibilities, preferred mediums of communication can vastly differ. Furthermore, different aspects of the project can have different level of importance to the different levels within a firm. For example, senior managers might be primarily concerned with schedule, material quantities and overall structural behavior. However, design engineers might be mainly concerned with detailed analysis and design involving individual member forces. Communication between the layers can be hindered by failing to understand the differing concerns of each team member. External communication can also suffer from a similar lack of alignment of priorities and mediums of communication. Architectural teams might be more visually inclined while project management teams might tend towards written communication. Automated Post Processing of Structural Analysis In order to bridge the gaps in communication both internally and externally, tools which are interactive, easy to use and highly visual are implemented. To this end, a custom program was developed by the author to automate the post processing of structural analysis results. The program reads information directly from the structural analysis model and generates interactive web pages displaying information of interest. Information ranging from story loads to drifts to material quantities can be quickly reported. This frees the design engineer from tedious manual manipulation of data and allows them to concentrate more value added tasks such as design exploration or architectural collaboration. Illustrated in Figure 24 is a screenshot of the custom program which allows for easy post processing of structural analysis. 59

12 Figure 24: Custom Program for Structural Analysis Result Reporting Figure 25 shows the interactive, easily shareable, web page reporting relevant structural information. This democratizes and distills the wealth of information that structural analysis produces. It also allows all members of the design team who may not be directly involved with the management of the analysis model, to understand, at their selected level of detail, structural behavior and performance. Figure 25: Web Based Reporting of Structural Analysis Common 3D Modeling Platform In order to communicate geometry variations and schematic structural sizes, utilizing a common 3D modeling platform with the architectural team is crucial. A common lightweight modeling environment allows easy visualization of structural members and its impact on the architectural design. This also provides a fast way to generate traditional 2D plans, elevations and sections as the design rapidly evolves. 60

13 Collaboration Figure 26: Bi-Directional Linkage of Structural Analysis and Rhino Internal efficiency and communication are the crucial first steps in delivering greater value to our clients. The key differentiator in the future for design and project delivery will be how the skills and experiences of the team can be effectively leveraged. Digital design tools have opened up previously inconceivable possibilities for architectural expression. In the previous two sections, this paper has shown the possibilities of using these same tools in custom ways to accelerate and communicate structural design. In this section, the paper explores ways to collaboratively explore the design space so that client s needs, architectural intent and structural requirements are fulfilled simultaneously. Floor Plate Geometry Exploration A simple example of leveraging digital design tools for architectural collaboration might be the exploring the location of corner columns in a typical floor plan. Usually, corner conditions want to be architecturally expressed for occupant views. This can be achieved by sliding the columns away from the corner. However, this creates a cantilever condition which might lead to excessive slab deflections which can complicate the façade design. The structural design team might explore the variation of the columns away from the corner and its effect on slab deflections. Illustrated in Figure 27 is a range of corner slab conditions with the supporting columns moved away from the corner. 61

14 Figure 27: Corner Column Location Exploration Leveraging bi-directional linkages to structural analysis, these geometries can be analyzed quickly and deflection performance obtained. Moving beyond linear modes of collaboration where geometries are traded back and forth between architect and engineer, custom tools allow the engineering team to proactively explore a range of geometries which might satisfy both architectural and structural considerations. Illustrated in Figure 28 is the result of structural analysis. With such quick analysis available, the design team can converge towards a mutually satisfying outcome in much shorter time frames. Force Trajectory Exploration Figure 28: Floor Plate Displacement Tracing force trajectories along a design surface is another potential avenue for design exploration leveraging digital design tools. In Figure 29, some common design spaces where force trajectory exploration might be illustrative are shown. The first situation is a core and outrigger lateral system, 62

15 which is often preferred due to its reduction of core size and limited impact on the architecture. Another commonly encountered structural situation is the design of transfer beams. Figure 29: Trajectory Studies Loading Profiles A custom component was written by the author to dynamically interact with external finite element software and trace principal force trajectory lines given a set of seed points. Figure 30 shows the raw principal force vectors in the finite element package and the final result from the custom tracing operation. Thus, in more complicated structures with multiple loads paths, where basic structural intuition might be misleading, this operation can be used to show stress concentrations and primary load flow. Figure 30: Filtered Trajectory Lines 63

16 Conclusion Digital design tools have significantly advanced within the architectural design community. The design community now has the opportunity to explore innovative, iconic designs that before only resided in the imagination of the designers. This paper has explored areas of innovation which might allow the structural community to collaborate more effectively with their architectural design clients. The paper began by exploring innovations in the internal efficiency realm. This area provides the foundation for effective project execution. Building upon this, the paper explored innovations in communication that are built upon a base of automation that aid the production of highly visual and interactive documentation. Finally, the paper explored digital design technologies from the perspective of provoking new possibilities for design exploration. These technologies will serve continue to serve as the foundation for innovative and iconic design projects in the future. 64