An alternative bid gives clients and bidders the opportunity to deliver a specified service functionally equivalent, but methodically or technically different. Used correctly, it can optimize schedule, cost, quality, and environmental and occupational safety. This is particularly relevant in areas such as concrete demolition and special demolition, building gutting and concrete cutting, rock demolition and tunnel construction, natural stone extraction, and special demolition. In practice, it often involves replacing conventional percussion or blasting technology with low vibration levels and reduced-noise approaches, such as the use of a concrete pulverizer or hydraulic rock and concrete splitters (rock wedge splitter and concrete splitter) with associated power units, in order to better meet ongoing-operations needs, emission limits, or structural analysis constraints.
Definition: What is meant by an alternative bid
An alternative bid in construction is an alternative solution proposal to a tender that deviates from the procurement documents but achieves the intended result in functional terms equivalently. It generally concerns the execution method, the construction materials, or the equipment technology as well as process and construction logistics. The basis is the conditions stated in the tender; alternative bids are usually permitted only if they are allowed and can be evaluated on a comparable basis. A separate presentation is customary, including a technical description, transparent costing, schedule, information on quality, safety, and environment, as well as the required evidence. Legal requirements and evaluation modes may vary by type of procurement and scope of services and should always be observed generally and carefully.
Objectives, occasions, and added value of alternative bids in construction
Alternative bids are used to minimize risks, reliably meet permitting conditions, or propose more economical and environmentally friendly procedures. Typical added values include lower vibration and noise emissions (e.g., via concrete pulverizer), reduced dust generation (e.g., by controlled splitting instead of percussion), higher execution quality (cleaner edges, less rework), and optimized processes in sensitive existing environments. In concrete demolition and special demolition, switching from conventional striking tools to concrete splitter, hydraulic splitter, or hydraulic demolition shear can significantly improve project execution.
Formal and technical requirements for an alternative bid
For an alternative bid to be evaluated quickly and fairly, it must be complete, clear, and verifiable. The following contents have proven effective:
- Scope of services: Precise description of the alternative method, equipment, and work steps (e.g., use of Concrete pulverizer or rock wedge splitter and concrete splitter, required hydraulic power pack, gripping and splitting sequences).
- Functional equivalence: Justification of how the tender objective is technically achieved (structural behavior, tolerances, surfaces, demolition depth, residual material condition).
- Costing and pricing: Transparent mapping to bill-of-quantities items, if applicable, separate alternative items with clear quantity and unit definitions; presentation of setup, standby, and construction logistics costs.
- Schedule and construction sequence: Sequences, interfaces, access, conveyance paths; handling of usage windows and noise control times.
- Quality, safety, environment: Measures for dust, noise, vibration, and water; disposal concepts; protection of existing components and utilities; evidence and measurement concepts.
- Evidence and suitability: References, procedural instructions, if applicable, field trial/test; information on maintenance and performance of the equipment used.
Ensuring comparability
For the award evaluation, comparability with the base bid is crucial. Helpful are identical structures, consistent quantity assumptions, uniform price structures, and clearly identified deviations. Where functional specifications are provided, fulfillment of performance criteria, including measurable parameters (e.g., maximum permissible vibration levels on the existing structure), should be demonstrated, supported by ground vibration monitoring where appropriate.
Typical alternative bids in demolition, deconstruction, and fit-out
In the following fields of application, alternative bids are frequently used to adapt methods to surrounding conditions, permits, or construction timeframes:
Building gutting and cutting
- Concrete pulverizer for slab and wall sections where percussion is restricted due to noise or vibration limits; precise separation reduces rework.
- Concrete demolition shear for mixed materials (reinforcement with concrete) to cleanly separate interfaces and improve purity in removal.
- Hydraulic power pack in compact form enables work in tight existing areas with limited power supply.
Concrete demolition and special demolition
- Concrete splitter and hydraulic splitter for controlled splitting of foundations, beams, or massive walls with limited edge influence.
- Hydraulic demolition shear for processing reinforced components when rapid switching between cutting and crushing is required.
- Concrete pulverizer for selective removal in buildings with ongoing operations (e.g., clinics, laboratory areas) to minimize vibrations and dust.
Rock excavation and tunnel construction
- Rock wedge splitter as an alternative to blasting vibrations in sensitive areas (close to existing structures, infrastructure) to achieve controlled crack propagation.
- Hydraulic splitter for wedges, niches, invert removal, and profile corrections with closely guided crack formation.
Natural stone extraction
- Controlled splitting for raw-block extraction with defined crack orientation to improve yield and reduce waste.
Special demolition
- Steel shear for the deconstruction of steel structures, bridge components, or industrial facilities where space is limited.
- Cutting torch for safe dismantling of tanks and pipelines, observing applicable protective measures.
Costing and cost efficiency of the alternative bid
The cost efficiency of an alternative bid in construction is measured not only by unit prices but by total costs and project risks. For alternative methods using concrete pulverizer or rock wedge splitter and concrete splitter, follow-on costs for rework, noise control, ground vibration monitoring, or remediation of damage to the existing structure often decrease. To facilitate evaluation, the following cost blocks should be clearly identified:
- Equipment technology (mobilization, changeovers, wear, hydraulic power pack, tool change times).
- Performance rates (m³/h in splitting, t/h in crushing, cutting speeds in steel).
- Construction logistics (access, load capacities, conveyance paths, intermediate storage, separation of fractions).
- Environmental and safety measures (dust suppression, noise reduction measures, ground vibration monitoring, protective enclosure, water management).
- Disposal and recovery (purity of fractions, particle size after processing, transport weights, recycling potential).
Environment, occupational health, and safety
Alternative bids are often chosen to reduce emissions and improve safety. Methods with controlled splitting and shear-based processing typically reduce noise and vibration levels as well as dust; this protects personnel and the existing structure. Appropriate dust-binding measures, safe handling of hydraulics, and forward-looking site logistics are essential. The relevant rules on noise, vibration, hazardous substances, and machine safety must be followed; specific requirements may vary by project and location.
Planning, sequence, and documentation
A robust alternative bid is based on a clear procedural instruction and verifiable results. Proven practices include test areas, measurement concepts (e.g., vibration, noise), binding acceptance parameters, incident management, and unambiguous documentation of actual quantities and qualities. This makes risks visible early and ensures comparability with the base bid.
Sample contents of a procedural instruction
- Objective and scope of the alternative method.
- Description of the equipment technology (e.g., concrete pulverizer, rock wedge splitter and concrete splitter, hydraulic power pack) and application limits.
- Process with takt planning, cutting and splitting sequences, residual thicknesses, safety measures.
- Quality assurance, measurement and test plans, acceptance and documentation scope.
- Occupational safety, environment, emergency and incident procedures.
- Logistics, disposal, sorting, and intermediate storage.
Risks, limits, and suitability assessment
Not every structure or boundary condition suits every method. For heavily reinforced or prestressed components, very strong concrete, complex integrations, or limited gripping points, performance can vary. Preliminary checks, sondages, and test drilling help optimize parameters such as splitting distances, notch geometries, cutting sequences, and approach angles of shears. Structural analysis, protection of the existing structure, and utility installation must be incorporated into planning.
Practice-oriented development of an alternative bid
For the write-up, a clear, objective presentation with the same structure as the base bid is recommended. One possible outline: 1) objective and functional equivalence, 2) method description (e.g., concrete pulverizer for selective deconstruction, hydraulic splitter for massive components), 3) performance and quality indicators, 4) schedule and logistics concept, 5) safety and environment, 6) costing with alternative items, 7) evidence/references. This produces a verifiable document that makes the benefits of the alternative approach transparent.
Reference to Darda GmbH products and application areas
Depending on the goal of the alternative bid, different tools and power packs come into consideration: concrete pulverizer for low-emission deconstruction in existing buildings, concrete splitter and hydraulic splitter for controlled separation of massive components or rock, hydraulic demolition shear and concrete demolition shear for flexible processing in mixed materials, steel shear for steel structures, and cutting torch for specific industrial applications. This technology finds concrete application in the stated fields of use—from concrete demolition and special demolition through building gutting and concrete cutting to rock excavation and tunnel construction, natural stone extraction, and special demolition—and can be practically justified within the alternative bid.