JILLIAN RALEIGH 583168
abpl90286_2013_sem1: construction methods a. jillian raleigh 583168
STICKS
task// to design and construct a bridge, crane and tower with a limited supply of material, acknowledging the forces on the structure and considering firmitas, utilitas, and venustas. to be built in a restricted timeframe. response// process of ideation and design development followed by construction phase: a crucial lesson in the art of construction and the relationship between vision and reality.
CHALLENGE//team + brief
IDEATION//precedent + concept
DESIGN//development via sketches, models + crits
CONSTRUCTION//fabrication of bridge, crane + tower
REFLECTION//thoughts
nathan hughes graphic design kitty winter graphic design
jil raleigh civil engineering tori allen creative direction
brief// to design and construct a bridge, crane and tower, reconstituting the limited supply of timber, plywood and rope to generate forms that acknowledge the forces on the structure (tension, compression, bending) and express the unique structural properties of the materials, while meeting fundamental architectural criteria: the Vitruvian triad (firmitas, utilitas, and venustas, or firmness, commodity and delight). the structures must be built by the teams in 2.5 hours, including deconstruction time.
aim// to gain an understand as well as the potential disco between vision and reality d of architecture and the impac and clients) on design.
david li industrial design lawrence rocha benavides interior design courtney foote fine arts
ding of construction technique, skills// diversity of ungraduate and work experience ontinuities in the relationship typical of the masters cohort: from graphic design to due to the practical limitations geotechnical engineering to abstract painting. ct of external forces (builders
tools// variety of equipment typical of domestic-scale building projects. /power drill, impact driver and claw hammer /spirit level, set square and tape measure /dropsaw, jigsaw, circular saw, handsaw and hacksaw /various drill bits (14mm spade, 3/8” hex head, phillips head, square-drive and 5mm).
materials// hardwood (F), machine-graded pine (MGP), plywood, rope and an assortment of fixings. the numbers following the timber code indicate the stress grading or structural capacity of the timber. the numbers following the “@” denotes the crosssectional dimension. /F17 /MGP10 /5mm ply
1 x 3600mm @ 90 x 45 3 x 3000mm @ 90 x 45 6 x 3000mm @ 70 x 35 1 x 3600mm @ 140 x 45 1200 x 2400mm
/10mm rope 10m /star pickets 3 x 900mm /M10 threaded rod, nuts and washers /variety of screws and nails
precedent// our team considered a number of existing structural themes as a conceptual basis for the designs, tending to promote asymmetrical compositions with a picturesque or whimsical quality: /bridge: webbed or cantilevered structures /crane: systems with multiple articulations /tower: angular or cylindircal trussed forms concept// the initial design phase involved the selection of elements of precedent models and creating a cohesive preliminary scheme, considering material consumption and construction sequence in addition to structural, utility and aesthetic aspects of the design. our team focused on incorporating trussed forms for structural integrity and modularity as a technique for streamlining construction.
crit session
development// the designs were refined in an iterative process of hand sketching, digital drawing and physical modelling, followed by regular crits with the lecturing team. digital modelling
design alterations were made subsquent to the crits either to better express the properties of the materials provided: /curved bridge deck to exhibit the pliability and flexural strenth of plywood /threaded rod connecting bridge deck and pod to demonstrate the shear capacity of bolts /trussed timber pods to reveal the strength of timber in compression and tension /rope bracing to show the tensile capacity of rope. physical modelling
or to resolve problems of constructability..
bridge// potential for buckling failure of the ply, or pull out failure of nails in the connection between ply and timber in the bridge deck, due to load on the crest of the deck. solution = run central beam along deck frame to support ply vertically. add beams along sides to restrain ply laterally. pod// our team anticipated difficulties in cutting precise angles on site based on observations during the consulting physical modelling phase. the engineer solution = attach timber bracing to face of column with a full lap joint, rather than between vertical struts with a butt joint (although having the vertical strut and brace in the same plane is ideal for force transfer). similar problem with vertical struts, but applying the same solution seemed detrimental to the aesthetic. our team decided to accept the challenge of angled cuts on site. resolving the pod design
crane// connection between crane boom and truss pod. solution = vertical member supporting the boom bolted to vertical strut of pod. clamp connection solution also considered, but deemed less reliable in terms of execution on site.
consulting the architect/builder
system of ropes for dual operability of the crane. solution = independent ropes attached to the boom and to the jib, running parallel over mast and down to operator behind the pod tower. the articulation of the crane proved to be the most challenging aspect of the design to resolve.
resolving the crane design
difficulty achieving precise dimensions
construction// the teams constructed the prototype bridge, crane and tower, in 3 x 2.5 hour sessions over 2 days. the construction sequence was intended to maximise the benefit of the modular design and minimise waste = bridge, crane, tower. as an added challenge, our team was assigned another design to build in the 3rd construction session (a bridge). our tower instructions were duly provided to another team.
bridge// our team recognised the bridge as the most ambitious project in terms of the amount of work, but had not appreciated the sheer volume of cutting necessary to complete the build. an intense 2.5 hours with the form not discernable prior to the rushed assembly in the last 15 minutes of the allocated time. the disadvantages of requiring precise angled cuts was immediately apparent.
ladder assembly
error in joint construction
deck assembly
pod assembly
attempted repair only partly successful
AS LESSON #1: FIRMIT
from s of elements generate length or 60 , 45 , 30 0, . gles (ie standardised an es gl an g in ur an meas 90deg) rather th . rm fo d se ideali generated by an
rate ficient and accu enables more ef e a t and to produc use of equipmen nger). neater and stro flush joint (ie.
assembling the bridge components
cutting the ply with the circular saw
wetting the ply prior to attaching to deck frame
LES
win 1// the curved ply deck proved to be strong and comfortable to walk on, as well as producing an aesthetic unique among the cohort.
avoi flan with if r of th
inst stro to slig non-
post-construction crit
SSON #2: FIRMITAS
id butt joints with elements nked on either side if dealing h amateur tradesmen, especially requiring orientation in the case he ladder rungs.
tead, opt for a full lap joint: onger, more reliable and faster construct, though utilitas is ghtly compromised by producing a -horizontal step surface.
LESSON #3: VENU STAS the pod and ladder detrac ted from the ply aesthe tic, complicati ng the formal compos ition and le ad in poor workmans g to hip due to th e time constraint. aim for a co hesive, single gesture, avoiding a fr enzied agglom eration of elements and the diff ic ulties of execution within a re st ri construction cted time.
deconstruction
2nd pod assembly
attaching the 1st and 2nd pods
2nd attempt at joint repair
improving team dynamic
crane// the precise angled cuts continued to plague our design, but the repetition of pod 1 enabled a more successful rendering of pod 2, with neater and stronger joints.
crane boom and jib assembly
fixing the pods to the ground
rope bracing tied with trucker’s hitch
attempt to gain more leverage with trucker’s hitch
pivot point for crane boom
pivot point for crane rope system
win 2// execution of dual movement of boom and jib. win 3// rope bracing, along with rope pulleys, proved efficient with respect to structural integrity and time, as well as enhancing the chaotic aesthetic of the form.
LESSON #4: FIRMITAS the boom conspicuous elements of ing in ult res e, not cut to correct siz messy connections. t existing always measure cuts agains gths are len elements to ensure correct.
LESSON #5: UTIL ITAS boom mechanis m too heavy to operate due to inadeq uate leverage , despite the addition of trucker’s hitc h. reduce boom self-weight substituting by F17 with 70x3 5 members (F17 seems ex cessive in te rms of strength in bending); increase mast length to increase leverage; incorporate pu lley system wi th rope through lugs attached to po ds.
post-construction crit
instructions provided by the other team
bridge 2// our review of the other team’s plans revealed some ambiguity as to design intent: had the designers meant for the deck to pivot or remain fixed as the entire structure pivoted? no means for controlled pivoting had been provided in the instructions and a global instability arises from the mass centroid location far beyond the base/ footprint of the structure with no restraining member. variation 1//our team opted to resolve the stability issue by halving the original 3.6m cantilever and tying 2 x ropes to the bridge superstructure back to star pickets embedded in the ground.
deconstruction
resizing materials
structure from previous session
our team considers the construction approach
leaving modular elements intact
solved by adding cross-member
continuation of counter-sinking short screws
difficulty fixing unrestrained vertical masts
variation 2//the vertical, parallel masts were unrestrained at the top, so attaching to base frame while maintaining a minimum clear distance was difficult. despite using the 2 x screws specified, the connection was effectively a pin joint prior to attaching bracing members. our team added a cross-member at the top of the masts to maintain the 500mm critical distance allowing the deck to be attached in a subsequent step.
avoiding weakening of the butt joint by not counter-sinking too far into the timber discussing the logic of the construction sequence
fitting the deck to the abutment frame
variation 3//the instructions indicated cross-members securing the bridge deck to the abutment frame had to be attached prior to insertion between the vertical masts. however, the cross-members logically had to be attached subsequent to insertion. otherwise, instructions had sufficient detail and diagrammatic clarity to execute the build.
variation 4//the instructions provided no indication of the intended location of the structure, so our team considered a number of options, attempting to capture the whimsical quality of the bridge. following advice from the lecturing team, our team selected the edge of the gully as the most suitable location, the void emphasising the philosophical commentary of the half-bridge.
win 4// progressive improvement in team organisation and skills
LESSON #6: FIRMITAS & VENUSTAS structure the decision to restrain the risk of any ted with ropes preven collapse. sufficient however, the 2 x ropes had port the sup to tensile capacity , so the 3.6m g tin jec original deck pro ned and rte sho be to d deck did not nee e been hav may tic the the dramatic aes preserved.
LESSON #7: UTILIT
AS & VENUSTAS
post-construct ion, our team discovered the shortening of the deck in terfered with the design intent the othe r team: to allow the st ructure to pivo t as the user crossed th e bridge.
post-construction crit
instructions must convey design intent to prev ent any miscon ceptions, perhaps a cont rolled pivot may have been devised during constr uction to realise the de sign vision.
tower// construction by another team yielded a reinterpretation of the aesthetic in an attempt to further develop the chaotic parti. the precise dimensions and angled cuts again proved a hindrance.
continuation of difficulty achieving precise dimensions
alteration of design motivated by aesthetics
difficulty with connection integrity due to alteration
reaction to alteration
LESSON #8: UTIL ITAS
the dimensio ns provide instructions were produc from the di gital model consequently far too p dimensions we re more suited physicists th an amateur with rudiment ary tools a time.
dimensions mu st be expre level of precis ion appropri context: ±50mm for a concre for a builder, ±1mm for a cabi
“enhanced” tower
ed in the ced directly l and were precise. the d to nuclear r tradesmen and limited
essed to a iate to the eter, Âą10mm inet-maker.
post-construction crit
LESSON #9: VENUSTAS resulted in alterations to the design original a misrepresentation of the mised the aesthetic intent and compro tower, the of ity egr structural int of having rendering the experience r team the ano by lt the tower bui inquishing more akin to that of rel of another a project to the control uction by architect rather than constr an obliging builder. vision and the relationship between a chasm. en oft is y lit constructed rea
reflection// despite the difficulties inherent in team assignments (balancing work load and delegating tasks), our team managed to accomplish the goals, though our projects had much room for improvement. our team found the experience extremely beneficial: to participate in the full construction cycle (consultation, ideation, design development and building), rather than ceasing involvement post-design (as is the case in most university courses encountered in my career thus far). thus, our team gained an appreciation of the art of design and construction and, as designers, have grown significantly through the process.