https://michaelzstern.com/references/Entries in the encyclopedia of Michael Stern, founder of JDS Development Group, on the mechanics of difficult urban development.en-ushttps://michaelzstern.com/taipei-101-and-the-visible-damper/https://michaelzstern.com/taipei-101-and-the-visible-damper/Wed, 07 Oct 2026 12:00:00 GMTHow Taipei 101 answers typhoons and earthquakes at once, and why its 660 tonne damper hangs in public view, from Michael Stern's reference pages.https://michaelzstern.com/view-corridors-and-view-cones/https://michaelzstern.com/view-corridors-and-view-cones/Wed, 07 Oct 2026 12:00:00 GMTLondon's vistas of St Paul's, Vancouver's mountain view cones and Toronto's point tower, three cities that build around a sightline. Michael Stern entry.https://michaelzstern.com/shanghai-tower-and-the-twist/https://michaelzstern.com/shanghai-tower-and-the-twist/Wed, 07 Oct 2026 12:00:00 GMTHow Shanghai Tower's makers found a 120 degree twist that cut wind load 24 percent and hung a second skin around nine stacked zones. Michael Stern entry.https://michaelzstern.com/dubai-and-the-megatall/https://michaelzstern.com/dubai-and-the-megatall/Wed, 07 Oct 2026 12:00:00 GMTWhat let a building pass 800 metres: a buttressed core, concrete pumped to 606 metres and setbacks shaped by wind tunnel testing. Michael Stern reference.https://michaelzstern.com/chicago-and-the-tall-building/https://michaelzstern.com/chicago-and-the-tall-building/Wed, 07 Oct 2026 12:00:00 GMTTwo Chicago generations compared: Fazlur Khan's steel tubes against the concrete tower of the 2000s, and the zoning behind each. Michael Stern reference.https://michaelzstern.com/tokyo-floor-area-and-sunlight/https://michaelzstern.com/tokyo-floor-area-and-sunlight/Wed, 07 Oct 2026 12:00:00 GMTA walk through Tokyo's rules: floor area by road width, the winter shadow test, slant planes and Marunouchi's special districts. Michael Stern reference.https://michaelzstern.com/hong-kong-building-on-slopes/https://michaelzstern.com/hong-kong-building-on-slopes/Wed, 07 Oct 2026 12:00:00 GMTThe podium tower, the plot ratio that sizes it and the slope safety system beneath it, Hong Kong's answer to steep ground. Michael Stern encyclopedia.https://michaelzstern.com/economics-of-skyscrapers/https://michaelzstern.com/economics-of-skyscrapers/Wed, 07 Oct 2026 12:00:00 GMTEconomic height, Barr and Ahlfeldt on why cities build tall, and the height premium that makes each floor dearer than the last. Michael Stern.https://michaelzstern.com/peer-review-economics/https://michaelzstern.com/peer-review-economics/Wed, 07 Oct 2026 12:00:00 GMTWhat a structural peer review and a facade mockup test cost, set against the cost of being wrong once at the Citicorp Center. Michael Stern encyclopedia.https://michaelzstern.com/schedule-float-and-sequencing-cost/https://michaelzstern.com/schedule-float-and-sequencing-cost/Wed, 07 Oct 2026 12:00:00 GMTFloat, the critical path, who owns the slack, and why a sequencing error on a tower is paid once in time and again in money. Michael Stern encyclopedia.https://michaelzstern.com/bid-dispersion/https://michaelzstern.com/bid-dispersion/Wed, 07 Oct 2026 12:00:00 GMTWhy bids spread on a building no bidder has built, and the alternates, allowances, clauses and mockups that narrow them. Michael Stern encyclopedia.https://michaelzstern.com/construction-cost-indices/https://michaelzstern.com/construction-cost-indices/Wed, 07 Oct 2026 12:00:00 GMTThe construction cost indices, ENR, Turner, RLB and Mortenson, what each tracks and what none sees on an unusual building. Michael Stern encyclopedia.https://michaelzstern.com/value-engineering/https://michaelzstern.com/value-engineering/Wed, 07 Oct 2026 12:00:00 GMTValue engineering as a function study, how it differs from cutting cost, and where a late saving resurfaces as a defect. Michael Stern encyclopedia.https://michaelzstern.com/contingency-and-risk-registers/https://michaelzstern.com/contingency-and-risk-registers/Wed, 07 Oct 2026 12:00:00 GMTDesign, bidding, construction and owner contingency through a project, the risk register behind them, and how a risk retires. Michael Stern encyclopedia.https://michaelzstern.com/cost-estimating-without-comparables/https://michaelzstern.com/cost-estimating-without-comparables/Wed, 07 Oct 2026 12:00:00 GMTHow estimators price a building that resembles nothing built before, from components and unit data to escalation. Michael Stern encyclopedia.https://michaelzstern.com/mockups-and-shop-drawings/https://michaelzstern.com/mockups-and-shop-drawings/Wed, 07 Oct 2026 12:00:00 GMTThe shop drawing cycle, the visual mockup and the submittal, and where facade errors are caught at the lowest price, in Michael Stern's encyclopedia.https://michaelzstern.com/steel-erection-sequence/https://michaelzstern.com/steel-erection-sequence/Wed, 07 Oct 2026 12:00:00 GMTHow a steel frame rises in tiers, is plumbed and bolted, and when steel beats concrete on a city site, in Michael Stern's encyclopedia.https://michaelzstern.com/sidewalk-sheds-and-protection/https://michaelzstern.com/sidewalk-sheds-and-protection/Wed, 07 Oct 2026 12:00:00 GMTThe sidewalk shed and overhead protection between a New York site and the street, who orders them and why they stay, from Michael Stern's encyclopedia.https://michaelzstern.com/special-inspections/https://michaelzstern.com/special-inspections/Wed, 07 Oct 2026 12:00:00 GMTWhat a New York special inspector verifies on site and what an independent peer reviewer checks on paper, from Michael Stern's encyclopedia.https://michaelzstern.com/excavation-support/https://michaelzstern.com/excavation-support/Wed, 07 Oct 2026 12:00:00 GMTSecant walls, slurry walls, soldier piles and tiebacks, and how a city hole is held open beside its neighbours, in Michael Stern's encyclopedia.https://michaelzstern.com/concrete-pumping-at-height/https://michaelzstern.com/concrete-pumping-at-height/Wed, 07 Oct 2026 12:00:00 GMTHow concrete is pumped hundreds of metres up a tower, what the mix must do to travel, and how mat pours are staged, in Michael Stern's encyclopedia.https://michaelzstern.com/tower-cranes-on-tight-sites/https://michaelzstern.com/tower-cranes-on-tight-sites/Wed, 07 Oct 2026 12:00:00 GMTHow a tower crane is tied, climbs and comes down on a hemmed in city block, and why the hoist beside it sets the pace, from Michael Stern's encyclopedia.https://michaelzstern.com/climbing-formwork/https://michaelzstern.com/climbing-formwork/Wed, 07 Oct 2026 12:00:00 GMTHow jump form and slipform rigs climb a concrete core, what the cycle depends on, and why the core sets the schedule, from Michael Stern's encyclopedia.https://michaelzstern.com/top-down-construction/https://michaelzstern.com/top-down-construction/Wed, 07 Oct 2026 12:00:00 GMTHow top down construction builds a basement and a tower at once, with plunge columns and slabs as props, in Michael Stern's encyclopedia of hard sites.https://michaelzstern.com/metal-cladding-engineering/https://michaelzstern.com/metal-cladding-engineering/Wed, 07 Oct 2026 12:00:00 GMTCopper, bronze, stainless and aluminum skins as engineering: patina rates, galvanic pairs, cleats that let sheet move, complex geometry. Michael Stern.https://michaelzstern.com/terra-cotta-as-a-modern-system/https://michaelzstern.com/terra-cotta-as-a-modern-system/Wed, 07 Oct 2026 12:00:00 GMTHow extruded terra cotta is made, glazed, clipped to a rail and drained as a rainscreen, and why it came back as a system, for Michael Stern's readers.https://michaelzstern.com/facade-access-and-maintenance/https://michaelzstern.com/facade-access-and-maintenance/Wed, 07 Oct 2026 12:00:00 GMTWho cleans and inspects the outside of a tower: building maintenance units, davits, monorails and New York's recurring facade inspection. Michael Stern.https://michaelzstern.com/cladding-wind-pressures/https://michaelzstern.com/cladding-wind-pressures/Wed, 07 Oct 2026 12:00:00 GMTWhy a cladding panel sees more wind than the frame, where the peaks sit on a tower, and how a tunnel turns them into a specification, for Michael Stern.https://michaelzstern.com/facade-mockups-and-testing/https://michaelzstern.com/facade-mockups-and-testing/Wed, 07 Oct 2026 12:00:00 GMTA walk through a facade test yard: the full size specimen, the chamber, the pressure box, the racking frame and the hose test. For Michael Stern.https://michaelzstern.com/glass-performance/https://michaelzstern.com/glass-performance/Wed, 07 Oct 2026 12:00:00 GMTWhat an insulated glass unit is made of, how coatings, size, lamination and geometry change it, and what Local Law 15 asks of it. Michael Stern's subject.https://michaelzstern.com/thermal-bridging/https://michaelzstern.com/thermal-bridging/Wed, 07 Oct 2026 12:00:00 GMTThermal bridging in tall facades as a chronology, from the 1973 energy crisis to Local Law 97 and the 2025 New York City energy code. Michael Stern.https://michaelzstern.com/facade-movement-and-tolerances/https://michaelzstern.com/facade-movement-and-tolerances/Wed, 07 Oct 2026 12:00:00 GMTHow a tower frame creeps, deflects and sways, how a facade expands on its own, and how joints and anchors take it all, in Michael Stern's field.https://michaelzstern.com/rainscreen-principle/https://michaelzstern.com/rainscreen-principle/Wed, 07 Oct 2026 12:00:00 GMTWhy a rainscreen lets rain past its face on purpose, how drained and pressure equalized cavities differ, and the materials that use it. Michael Stern.https://michaelzstern.com/unitized-curtain-wall/https://michaelzstern.com/unitized-curtain-wall/Wed, 07 Oct 2026 12:00:00 GMTHow unitized curtain wall is built in a factory, hung from a slab edge, jointed for movement and drained, in Michael Stern's subject of tall buildings.https://michaelzstern.com/development-rights-programs-elsewhere/https://michaelzstern.com/development-rights-programs-elsewhere/Wed, 07 Oct 2026 12:00:00 GMTSeattle, San Francisco, Hong Kong, Tokyo and Mumbai each let unused building capacity travel under local rules. A comparison from Michael Stern's field.https://michaelzstern.com/building-over-rail-yards-and-highways/https://michaelzstern.com/building-over-rail-yards-and-highways/Wed, 07 Oct 2026 12:00:00 GMTHow platforms make new ground over live tracks and roads, from Chicago to London: caissons, rafts, trusses, decks. A subject Michael Stern follows.https://michaelzstern.com/development-rights-in-the-public-record/https://michaelzstern.com/development-rights-in-the-public-record/Wed, 07 Oct 2026 12:00:00 GMTWho records a transfer of New York development rights, where ACRIS files it, and why a survey cannot show what moved. A Michael Stern subject entry.https://michaelzstern.com/high-line-transfer-corridor/https://michaelzstern.com/high-line-transfer-corridor/Wed, 07 Oct 2026 12:00:00 GMTHow the 2005 West Chelsea rezoning let owners under a disused viaduct sell bulk across the district, the papers filed, and what rose.https://michaelzstern.com/theater-subdistrict-transfers/https://michaelzstern.com/theater-subdistrict-transfers/Wed, 07 Oct 2026 12:00:00 GMTMichael Stern subject note: how a listed Broadway house sells floor area across its subdistrict, the fund it pays, and the contrast with landmarks.https://michaelzstern.com/hudson-yards-transfer-district/https://michaelzstern.com/hudson-yards-transfer-district/Wed, 07 Oct 2026 12:00:00 GMTA walk across the Eastern Rail Yard deck: caissons between live tracks, trusses over the throat, and the district that puts bulk on it.https://michaelzstern.com/cantilevers-over-neighbours/https://michaelzstern.com/cantilevers-over-neighbours/Wed, 07 Oct 2026 12:00:00 GMTWhy New York towers lean out over low neighbors, the bought floor area and easements behind it, and the fire analysis the code demands.https://michaelzstern.com/party-walls/https://michaelzstern.com/party-walls/Wed, 07 Oct 2026 12:00:00 GMTShared walls from Rome to the New York fire limits, the codes that set their thickness, and what a new building may do at the line.https://michaelzstern.com/light-and-air-easements/https://michaelzstern.com/light-and-air-easements/Wed, 07 Oct 2026 12:00:00 GMTThe 30 foot rule behind a legal window, a neighbor's recorded promise not to build, the tower it shapes, and the older English idea.https://michaelzstern.com/zoning-lot-mergers/https://michaelzstern.com/zoning-lot-mergers/Wed, 07 Oct 2026 12:00:00 GMTThe declaration that merges tax lots for zoning, who signs or waives, the agreement that moves bulk, and a Brooklyn case.https://michaelzstern.com/landmark-transfers/https://michaelzstern.com/landmark-transfers/Wed, 07 Oct 2026 12:00:00 GMTHow a designated landmark sends unbuilt floor area: the LPC maintenance program, the City Planning certification and East Midtown.https://michaelzstern.com/transferable-development-rights/https://michaelzstern.com/transferable-development-rights/Wed, 07 Oct 2026 12:00:00 GMTWhat a transferable development right is, how sending and receiving areas are drawn, how banks and ratios work, and New York's variants.https://michaelzstern.com/building-code-and-zoning/https://michaelzstern.com/building-code-and-zoning/Wed, 07 Oct 2026 12:00:00 GMTTwo rulebooks on one desk: what the Zoning Resolution measures, what the Building Code measures, and how a plan examiner reads both.https://michaelzstern.com/city-of-yes/https://michaelzstern.com/city-of-yes/Wed, 07 Oct 2026 12:00:00 GMTEleven questions on the City of Yes housing text: floor area, heights, parking, conversions, and what the Council altered.https://michaelzstern.com/special-districts/https://michaelzstern.com/special-districts/Wed, 07 Oct 2026 12:00:00 GMTHow a special district layers its own use, bulk and transfer rules onto base zoning, compared across Midtown, the theaters and downtown.https://michaelzstern.com/inclusionary-housing-bonus/https://michaelzstern.com/inclusionary-housing-bonus/Wed, 07 Oct 2026 12:00:00 GMTVoluntary and mandatory inclusionary housing as zoning mechanisms: how bonus floor area is earned and what the newer preference changed.https://michaelzstern.com/mechanical-voids/https://michaelzstern.com/mechanical-voids/Wed, 07 Oct 2026 12:00:00 GMTHow mechanical space escaped the count of floor area, how tall empty floors lifted towers, and what the text amendment changed.https://michaelzstern.com/zoning-lot-and-tax-lot/https://michaelzstern.com/zoning-lot-and-tax-lot/Wed, 07 Oct 2026 12:00:00 GMTThe zoning lot, not the tax lot, is the unit the Resolution measures; how a declaration creates one and what a merger binds.https://michaelzstern.com/ulurp/https://michaelzstern.com/ulurp/Wed, 07 Oct 2026 12:00:00 GMTThe charter's land use clock stop by stop: certification, community board, borough president, Commission, Council and mayor.https://michaelzstern.com/special-permits-and-variances/https://michaelzstern.com/special-permits-and-variances/Wed, 07 Oct 2026 12:00:00 GMTWhere compliance ends and asking begins: the five findings a variance needs and the lighter test for a special permit.https://michaelzstern.com/sky-exposure-plane/https://michaelzstern.com/sky-exposure-plane/Wed, 07 Oct 2026 12:00:00 GMTWhat a sky exposure plane is, why a slope governs bulk better than a height cap, and where the plane still rules New York towers.https://michaelzstern.com/floor-area-ratio/https://michaelzstern.com/floor-area-ratio/Wed, 07 Oct 2026 12:00:00 GMTFloor area ratio as a mechanism: the two numbers in the fraction, what the count includes, and how a multiplier becomes a building.https://michaelzstern.com/landmark-conversions-elsewhere/https://michaelzstern.com/landmark-conversions-elsewhere/Wed, 07 Oct 2026 12:00:00 GMTTwo Giles Gilbert Scott power stations converted two ways, with Hearst Tower and the King's Cross granary beside them, read for Michael Stern's subject.https://michaelzstern.com/masonry-and-terra-cotta-restoration/https://michaelzstern.com/masonry-and-terra-cotta-restoration/Wed, 07 Oct 2026 12:00:00 GMTOne terra cotta facade read part by part: unit, anchor, joint, survey, probe, replacement, glaze, inspection cycle, window. Michael Stern's subject.https://michaelzstern.com/building-beside-a-landmark/https://michaelzstern.com/building-beside-a-landmark/Wed, 07 Oct 2026 12:00:00 GMTThe order imposed when a foundation goes in beside a designated New York building: footings, support, monitoring, limits. Michael Stern's subject.https://michaelzstern.com/rooftop-additions-on-landmarks/https://michaelzstern.com/rooftop-additions-on-landmarks/Wed, 07 Oct 2026 12:00:00 GMTThe staff level rule for a rooftop addition on a New York landmark, the visibility test behind it and the hearings that made it, in Michael Stern's field.https://michaelzstern.com/facade-retention/https://michaelzstern.com/facade-retention/Wed, 07 Oct 2026 12:00:00 GMTHow a kept facade is held while the building behind is replaced: temporary steel, ties, movement limits and the new frame, in Michael Stern's subject.https://michaelzstern.com/secretary-of-the-interior-standards/https://michaelzstern.com/secretary-of-the-interior-standards/Wed, 07 Oct 2026 12:00:00 GMTThe ten federal Standards for Rehabilitation, the people who apply them and how a tax credit reviewer reads them, in Michael Stern's subject.https://michaelzstern.com/interior-landmarks/https://michaelzstern.com/interior-landmarks/Wed, 07 Oct 2026 12:00:00 GMTWhat New York protects when it designates a room, the access rule, the named features, and how a conversion carries a hall, in Michael Stern's subject.https://michaelzstern.com/designation-reports/https://michaelzstern.com/designation-reports/Wed, 07 Oct 2026 12:00:00 GMTA New York City landmark designation report read against a National Register nomination, what each protects and leaves open, in Michael Stern's subject.https://michaelzstern.com/certificate-of-appropriateness/https://michaelzstern.com/certificate-of-appropriateness/Wed, 07 Oct 2026 12:00:00 GMTA walk through the New York Landmarks permit that needs a hearing, from staff review to the full Commission and the record, in Michael Stern's field.https://michaelzstern.com/elevator-strategy/https://michaelzstern.com/elevator-strategy/Wed, 07 Oct 2026 12:00:00 GMTA chronology of the tower elevator, from the 1870 Equitable Building to carbon fibre rope, and the core area each step saved. For Michael Stern's readers.https://michaelzstern.com/transfer-structures/https://michaelzstern.com/transfer-structures/Wed, 07 Oct 2026 12:00:00 GMTTransfer girders, trusses, slabs and walking columns, the rule they break and New York's history of breaking it, from the Michael Stern encyclopedia.https://michaelzstern.com/mat-foundations-and-caissons/https://michaelzstern.com/mat-foundations-and-caissons/Wed, 07 Oct 2026 12:00:00 GMTManhattan schist, the bedrock myth, and how mats, caissons and rock sockets carry a tower into the ground. An entry in the Michael Stern encyclopedia.https://michaelzstern.com/tube-structures/https://michaelzstern.com/tube-structures/Wed, 07 Oct 2026 12:00:00 GMTWhy Fazlur Khan's framed, trussed and bundled tubes ruled the 1970s and why the concrete core took over. A Michael Stern encyclopedia entry.https://michaelzstern.com/high-strength-concrete/https://michaelzstern.com/high-strength-concrete/Wed, 07 Oct 2026 12:00:00 GMTTwo measures of a concrete column, strength at 28 days and shortening over decades, with mix design, pumping and creep. Michael Stern's structure series.https://michaelzstern.com/outriggers-and-belt-trusses/https://michaelzstern.com/outriggers-and-belt-trusses/Wed, 07 Oct 2026 12:00:00 GMTA floor by floor walk to the mechanical level where an outrigger couples core to perimeter columns, explained for Michael Stern's encyclopedia.https://michaelzstern.com/core-walls/https://michaelzstern.com/core-walls/Wed, 07 Oct 2026 12:00:00 GMTWhat a concrete core carries, how jump and slip forms raise it, and what it takes from every floor plate, in Michael Stern's structure cluster.https://michaelzstern.com/what-the-ctbuh-measures/https://michaelzstern.com/what-the-ctbuh-measures/Wed, 07 Oct 2026 12:00:00 GMTArchitectural top, uppermost floor in use, and tip, the 1998 spire ruling and the vanity height study, in Michael Stern's subject.https://michaelzstern.com/slender-towers-around-the-world/https://michaelzstern.com/slender-towers-around-the-world/Wed, 07 Oct 2026 12:00:00 GMT432 Park, Highcliff, Australia 108, Collins House and a Brighton seaside tower: slender towers and their damping, surveyed within Michael Stern's subject.https://michaelzstern.com/damping-stiffness-and-mass/https://michaelzstern.com/damping-stiffness-and-mass/Wed, 07 Oct 2026 12:00:00 GMTThree quantities behind a tower's resonant response, what each costs to change and why damping comes last: a mechanism entry in Michael Stern's subject.https://michaelzstern.com/building-shape-and-wind/https://michaelzstern.com/building-shape-and-wind/Wed, 07 Oct 2026 12:00:00 GMTSetbacks, tapers, softened corners, open floors and porous crowns: the shaping moves that weaken vortex shedding, in Michael Stern's supertall subject.https://michaelzstern.com/wind-tunnel-testing/https://michaelzstern.com/wind-tunnel-testing/Wed, 07 Oct 2026 12:00:00 GMTBoundary layer tunnels, pressure taps, aeroelastic models and why the neighbours go on the turntable, in the engineering that is Michael Stern's subject.https://michaelzstern.com/tuned-mass-dampers/https://michaelzstern.com/tuned-mass-dampers/Wed, 07 Oct 2026 12:00:00 GMTThe pendulum and the sliding mass compared, what Taipei 101's damper did in a typhoon, and what a damper changes and cannot, from Michael Stern's subject.https://michaelzstern.com/vortex-shedding/https://michaelzstern.com/vortex-shedding/Wed, 07 Oct 2026 12:00:00 GMTWhy a steady moderate wind can unsettle a slender tower more than a storm, the across wind mechanism Michael Stern treats as the governing problem.https://michaelzstern.com/occupant-comfort-criteria/https://michaelzstern.com/occupant-comfort-criteria/Wed, 07 Oct 2026 12:00:00 GMTMilli g acceleration, the thresholds people notice and the return periods behind them: the comfort criterion at the heart of Michael Stern's subject.https://michaelzstern.com/slenderness-ratio/https://michaelzstern.com/slenderness-ratio/Wed, 07 Oct 2026 12:00:00 GMTHow base to height is measured, why seven to one was the old ceiling and twenty to one is now built, a chronology from Michael Stern's supertall subject.https://michaelzstern.com/air-rights/https://michaelzstern.com/air-rights/Wed, 07 Oct 2026 12:00:00 GMTHow New York counts air rights in floor area, which lots may send them, the three routes they travel and the records that prove it, from Michael Stern.https://michaelzstern.com/zoning-and-entitlements/https://michaelzstern.com/zoning-and-entitlements/Wed, 07 Oct 2026 12:00:00 GMTHow New York zoning splits a project into automatic and discretionary approvals, what each route gives up, and the order they run in.https://michaelzstern.com/underwriting-without-comparables/https://michaelzstern.com/underwriting-without-comparables/Wed, 07 Oct 2026 12:00:00 GMTHow a building with no precedent is evaluated: priced by its parts, carried as a class, its risks correlated and ordered for resolution. Michael Stern.https://michaelzstern.com/landmark-conversion/https://michaelzstern.com/landmark-conversion/Wed, 07 Oct 2026 12:00:00 GMTWhat New York preservation review covers, how a protected building and new construction meet, and where Michael Stern's subject sits in it.https://michaelzstern.com/supertall-engineering/https://michaelzstern.com/supertall-engineering/Wed, 07 Oct 2026 12:00:00 GMTThe comfort criterion, moderate against severe wind, and the price of tunnel tests and dampers: the pillar of Michael Stern's supertall engineering.