Beam-column joints are addressed in the context of current design procedures and performance criteria for reinforced concrete ductile frames subjected to large earthquake motions. Attention is drawn to the significant differences between the pertinent requirements of concrete design codes of New Zealand and the United States for such joints. The difference between codes stimulated researchers and structural engineers of the United States, New Zealand, Japan and China to undertake an international collaborative research project. The major investigators of the project selected issues and set guidelines for co-ordinated testing of joint specimens designed according to the codes of the countries. The tests conducted at the University of Canterbury, New Zealand, are reported. Three full-scale beam-column-slab joint assemblies were designed according to existing code requirements of NZS 3101:1982, representing an interior joint of a one-way frame, an interior joint of a two-way frame, and an exterior joint of a two-way frame. Quasistatic cyclic loading simulating severe earthquake actions was applied. The overall performance of each test assembly was found to be satisfactory in terms of stiffness, strength and ductility. The joint and column remained essentially undamaged while plastic hinges formed in the beams. The weak beam-strong column behaviour sought in the design, desirable in tall ductile frames designed for earthquake resistance, was therefore achieved. Using the laws of statics and test observations, the action and flow of forces from the slabs, beams and column to the joint cores are explored. The effects of bond performance and the seismic shear resistance of the joints, based on some postulated mechanisms, are examined. Implications of the test results on code specifications are discussed and design recomendations are made.
The University of Canterbury's E-Learning team's temporary office in the James Hight building. The photographer comments, "First looks at our new temporary (maybe) office space. Our group will stay here until April or May 2011, then will move to another floor in the Central Library. Foyer lifts etc. Female toilets are off the foyer to the left. These lifts start at Level 2 of the Library, and are heavily used by students. (Once the building is repaired after the earthquake; several floors are still in a mess)".
Photograph captioned by BeckerFraserPhotos, "Central Library with the books now cleared off the floor in this part".
Emergency and security staff members prepare to enter the 6th floor of the Registry building to retrieve work from the offices there.
Emergency and security staff members prepare to enter the 6th floor of the Registry building to retrieve work from the offices there.
Emergency and security staff members prepare to enter the 6th floor of the Registry building to retrieve work from the offices there.
Emergency and security staff members prepare to enter the 6th floor of the Registry building to retrieve work from the offices there.
Emergency and security staff members prepare to enter the 6th floor of the Registry building to retrieve work from the offices there.
Nilgun Kulpe a counsellor with Relationship Services in Christchurch who was working on the 5th floor of the CTV building when the earthquake struck.
Photograph captioned by BeckerFraserPhotos, "Books on the floor of the Sumner Library, seen through the front window".
Photograph captioned by BeckerFraserPhotos, "Books on the floor of the Sumner Library, seen through the front window".
A photograph captioned by BeckerFraserPhotos, "The dramatically sloping floor of the Hotel Grand Chancellor car park".
A photograph of a crack in the floor of the Diabetes Centre. The crack has been filled in.
A photograph of an office in the Diabetes Centre. Files have fallen off the bookcase and lie on the floor.
A photograph of an office in the Diabetes Centre. Files have fallen off the desk and lie on the floor.
A photograph of the shop in the Diabetes Centre. Products have fallen off the shelves and lie on the floor.
The ANZ Bank Chambers on the corner of High and Lichfield Streets. WORLD, a clothing store, was housed on the ground floor.
Damage to an apartment complex on Durham Street. The building has collapsed on the ground floor level, and the concrete block fence collapsed.
Photograph captioned by BeckerFraserPhotos, "Press Building, Cathedral Square. Top floor collapsed during the February 22 earthquake".
Photograph captioned by BeckerFraserPhotos, "Press Building, Cathedral Square. Top floor collapsed during the February 22 earthquake".
Photograph captioned by BeckerFraserPhotos, "Central Library with the books now cleared off the floor in this part".
A photograph of a building on Cashel Street. Some of the windows on the bottom floor have been boarded up with plywood.
A member of the emergency team climbing the stairs on the first floor of the Registry Building, on the way to retrieve important items.
The former Government Life building in Cathedral Square. A couple of windows have been broken and a window on the ground floor has been boarded up.
A photograph of a room in the Diabetes Centre. Boxes and files have fallen off the bookcases and spread out across the floor.
A photograph of a room in the Diabetes Centre. Boxes and files have fallen off the bookcases and spread out across the floor.
Tools laid out on the concrete floor of the partially constructed Pallet Pavilion. Extension cords have been laid behind them.
A member of the USAID Disaster Assistance Response Team (DART) drilling a hole in the floor of a kitchen.
A photograph submitted by Gaynor James to the QuakeStories website. The description reads, "DTZ building going, 20 July 2011. A small crowd watches the demolition …There is an eerie silence- no excited buzz – people watching yet another part of their history turning into rubble. The wrecking ball, delicately positioned, drops and is followed by the cracking and rending of floor after floor and the debris tumbles down … It starts to clear and an extraordinary sight greets us. Hundreds and hundreds of sheets of paper drift down like giant confetti.".
Photograph captioned by Fairfax, "Earthquake damage in central Christchurch after a 6.3 earthquake. Second floor of The Press building".